really need something new to read, and since that period is one of the most interesting in history (imo), i want to read something of that. so what the hell, might as well ask the historians who know their sources for the books! online .pdfs preferable, but it's fine even without!
Check out the Peoples of Europe series. They're getting old but the scholars are all top notch and incorporate archaeology: https://www.amazon.com/Lombards-Peoples-Europe-Neil-Christie/dp/0631182381/ref=sr_1_1?ie=UTF8&qid=1479047528&sr=8-1&keywords=the+lombards+peoples+of+europe.
Fairly comprehensive and not over reliant on questionable narrative sources.