Tim - you might want to also take a look at Curt Lyles' kits (Curt's Blacksmith Shop) - he makes a nice early style iron mounted rifle kit with sleek lines, that uses the Chambers early Viriginia/English lock. I've seen some very nice rifles made from these. Tip Curtis, MBS, and TVM all have stock patterns that would work. If you are willing to do more work, Knob Creek has some very nice early pattern stocks that you can get inlet for the barrel, but you will have to inlet the lock and everything else. But you will save some money and have more leeway if you do this.
You could "kit bash" - start with a basic stock with the barrel and lock inlet from one of the suppliers but mix up the hardware to emulate the style you want. And that way, you won't have a standard kit gun - it will be more unique.
The architecture on the early style House guns is similar to some of the early Lancaster and other stock kit patterns out there, straight combm, but has just a slight curve to the toe line, which you can add. And if you inlet your own buttplate you can adjust the pitch of the butt and comb angle a bit to your liking.
So if it were me, I would find a pattern that offers the general architecture with enough wood to shape to your liking, and barrel and maybe the lock you like already inlet, and build around that. Most precarve stocks have enough wood to allow some shaping, and most companies will let you leave off the guard, buttplate etc so you can use ones of your liking.
If you do not need hand forged hardware, MBS sells a set of steel castings very similar to the guard and buttplate on the House Brothers rifle that is being raffled off, and you can make your own sideplate easily. Also - Mark Tornichio has some photos of some really nice wide early style forged buttplates he might be selling soon in the "Items for Sale" section - one of these would be perfect for a gun of that style and those wide early plates are not difficult to fit.
Good luck
Guy