The 60th Royal American Regiment also known as the King's Royal Rifle Corps. was made up of American colonists and some British volunteers. The 62nd was raised during the Seven Years War, and fought in many of the famous battles. The regiment help some positions for foreigners such as Swiss, German, Scot, Irish, as officers. A first for a British Regular Force.

Regular line forces were usually brought over from Britain, and while they may have recruited mainly in Britain, some were colonists as well. Provincial militias are usually easier to recruit for colony defense, since the commissions aren't as high, but the discipline is significantly lower in comparison. However, some Provincial units did show professional discipline, such as Virginia Regiment with George Washington at the helm. The Virginia Regiment went through constant drills and practices, quite uncommon for a militia.

I maybe going a bit off your question, but during the Revolutionary war colonists could join regular forces. This was especially done in the Southern Campaign with Cornwallis. Just to show an example and a continue of the idea.