An example that comes to mind is an account in Yngvars saga víðförla, attributed to Oddr Snorrason (although this is disputed). Bear in mind that this would have been recorded well past the events that it portrays (although closer to the time frame depicted than is the case in many sagas). Also the details of accounts in sagas should be taken with a grain of salt. However, they are useful in that they show that stories of this sort of thing were in circulation at the time.

A translation by Peter Tunstall is below source

1. Of Aki and King Eirik

There was a king called Eirik who ruled over Sweden. He was called Eirik the Victorious. He married Sigrid the Proud but separated from her because of her difficult moods, for she was a very quarrelsome woman and made an issue out of everything that happened. He gave her Gautland. Their son was Olaf the Swede.

At that time, Jarl Hakon ruled over Norway and had many children, but we will just say something about one of his daughters who was called Aud. King Eirik had a daughter too who is not named. A Swedish chieftain called Aki asked for her hand, but the king didn't much rate the idea of giving away his daughter to a commoner. Shortly afterwards a district king from Russia in the east asked for her and Eirik saw fit to give the girl to him, and she went east with him to Russia. A bit later, Aki came unannounced, took this king by surprise, killed him and carried off Eirik's daughter back home with him to Sweden, and married her. Eight chieftains made a pact with Aki, in this plot, and they remain thus for a while under King Eirik's displeasure, as the king didn't want to fight with them and thereby cause great loss of life among his own people within the land. Aki and his wife had a son, who was called Eymund.

After this, Aki offers to make peace with the king for his rashness. The king was agreeable to that. And now, when this had come to pass, King Eirik asks for Aud, the daughter of Jarl Hakon of Norway. The Jarl assented, although he made it known that he would have preferred not to have Eirik let his self-appointed son-in-law sit with impunity as high as himself in Sweden. Now the woman was promised and the wedding arranged, and now messages are once again exchanged between Aki and the king. And Aki invites the king to set his own terms, except for outlawry and confiscation of his estates, and they agree to that. The king now makes preparations for the wedding and invites the chieftains of the land: naming Aki, his son-in-law, first, and the eight chiefs who were allied to him.

2. Of Eymund and the Killing of Aki

On the appointed day, Jarl Hakon came from Norway to Sweden, and there were great multitudes of people at Uppsala, for all the most important men in Sweden were there. There were a lot of big halls put up there since many chieftains with large followings had come, although Aki's following was the largest, excepting those of King Eirik and Jarl Hakon. So the second biggest hall was prepared for Aki. The king's daughter wasn't there, or their son, because the king's offer didn't seem trustworthy.

Now they sit at the banquet for a time with much cheer and mirth. At the beginning of the feast, Aki had kept a good look out for his own safety, but less so as the wedding went on, till the feast was nearly done and there was just one night left. Then King Eirik takes them all by surprise and killed all eight of the chiefs who'd been opposed to him, and Aki likewise. After this, the feast was broken up. Jarl Hakon went to Norway and everyone to their own homes. This plot is attributed by some to Jarl Hakon, and some say that he himself was among the killers.

While this does not directly relate to the Red Wedding it is similar enough to be of note. Murders - even mass murders - at feasts and banquets appear in multiple sagas.

We see this in a passage from the Ynglinga saga as well:

40. THE BURNING IN UPSAL.

Then Ingjald, King Onund's son, came to the kingdom. The Upsal kings were the highest in Sweden among the many district-kings who had been since the time that Odin was chief. The kings who resided at Upsal had been the supreme chiefs over the whole Swedish dominions until the death of Agne, when, as before related, the kingdom came to be divided between brothers. After that time the dominions and kingly powers were spread among the branches of the family as these increased; but some kings cleared great tracts of forest-land, and settled them, and thereby increased their domains. Now when Ingjald took the dominions and the kingdom of his father, there were, as before said, many district-kings. King Ingjald ordered a great feast to be prepared in Upsal, and intended at that feast to enter on his heritage after King Onund his father. He had a large hall made ready for the occasion -- one not less, nor less sumptuous, than that of Upsal; and this hall was called the Seven Kings Hall, and in it were seven high seats for kings. Then King Ingjald sent men all through Sweden, and invited to his feast kings, earls, and other men of consequence. To this heirship-feast came King Algaut, his father-in-law; Yngvar king of Fjadryndaland, with his two sons, Alf and Agnar; King Sporsnjall of Nerike; King Sighvat of Aattundaland: but Granmar king of Sodermanland did not come. Six kings were placed in the seats in the new hall; but one of the high seats which Ingjald had prepared was empty. All the persons who had come got places in the new hall; but to his own court, and the rest of his people, he had appointed places at Upsal. It was the custom at that time that he who gave an heirship-feast after kings or earls, and entered upon the heritage, should sit upon the footstool in front of the high seat, until the full bowl, which was called the Brage-beaker, was brought in. Then he should stand up, take the Brage-beaker, make solemn vows to be afterwards fulfilled, and thereupon empty the beaker. Then he should ascend the high seat which his father had occupied; and thus he came to the full heritage after his father. Now it was done so on this occasion. When the full Brage-beaker came in, King Ingjald stood up, grasped a large bull's horn, and made a solemn vow to enlarge his dominions by one half, towards all the four corners of the world, or die; and thereupon pointed with the horn to the four quarters. Now when the guests had become drunk towards evening King Ingjald told Svipdag's sons, Gautvid and Hylvid, to arm themselves and their men, as had before been settled; and accordingly they went out, and came up to the new hall, and set fire to it. The hall was soon in a blaze, and the six kings, with all their people, were burned in it. Those who tried to come out were killed. Then King Ingjald laid all the dominions these kings had possessed under himself, and took scatt from them.