Ok, so America lost the revolution, say. Would there have been American peerages? Would there be Men sitting in parliament who were supposedly representing the Colonists? I know why the war was fought (taxation without representation), but surely King James would have had to make some kind of decision on that point, eventually.
There never were in other colonies. Occasionally someone would be raised to the peerage, but it was just a standard British peerage, and representation in the House of Commons was never extended beyond the UK proper (Malta almost got it in the 1950s, but ultimately decided to head toward independence rather than integration).
No. There were distinct kingdoms of England, Scotland and Ireland, and each had its own peerage. Then Scotland and England were united into the Kingdom of Great Britain, and after that there was a peerage of Great Britain. And then Great Britain and Ireland were united into a single kingdom, after which you have the peerage of the United Kingdom.
There was never a kingdom of America or a kingdom of Massachusetts, so no separate peerages for those places. There was nothing to stop a British subject born in, or settled in, Massachusetts (say) from being elevated to the peerage as a peer of Great Britain or a peer of Ireland, but I doubt that it ever happened. Peerages were a matter of patronage; to get a peerage you needed to be well-connected at court, politically influential or important, etc, etc, and there was also not much point in seeking a peerage if you weren’t going to take advantage of by by going to court, participate in the House of Lords, etc. So it wouldn’t have made a lot of sense from the point of view of either side in the transaction.
If the American revolution had never taken place, it might have developed like Canada or Australia, first with continuing local self-government (depending on the exact local circumstances, with or without occasional violent political upsets), then as a more or less independent Dominion within the Empire and ultimately wholly independent member of the Commonwealth. So no direct representation in the Commons, possibly the likes of Washington, Jefferson and Franklin offered British peerages, mainly as an honorific rather than expecting them to represent American interests in Parliament day to day. But once you get into speculation about how a semi-independent America still under the Crown would have dealt with a British parliament’s eventual desire to abolish slavery…
For what it’s worth, there have a number of Canadians who have sat in the House of Lords. Lord Mount Stephen, for example.