I kind of am getting ready to build my dream gun - been fiddling with the plans today, as a matter of fact. A big, iron-mounted proto-mountain rifle with an open-bow triggerguard and a round-faced lock closely based on an original.
I need a smoothbore, though (for a given value of "need," naturally) and for some reason instead of a nice, practical little fowling piece I've hankering after a musket or waterfowling piece. A composite musket or American-made fowling piece cobbled together out of disparate parts sounds like a fun project, with plenty of room for individual taste and without the constraints of copying a particular pattern or even a particular school. The problem is the lock, as there aren't any commercial locks that are really large enough for what I have in mind. I'd either have to assemble one of those sets of raw castings or scratchbuild one.