Not knowing how limited your funds are, this idea may be beyond them.
Pecatonica River offers a Kentucky style pistol "kit" in Flintlock or Precussion.
It has a 15/16ths octagon which should be available in .50 caliber.
Sorry, but my price list is several years old. At the time it was published the cost for one of these kits was given as $246 in Flint or $227.50 in Precussion. This did not include the cost of the wood. Their pistol size wood was listed at 28.50 for straight Maple, $45 for Premium Curly Maple, $33 for Cherry or Walnut.
That would make a precussion pistol in walnut cost about $260.50
As I say, the prices may be a little higher now, but it's food for thought.
Further thought is that Dick (owner of Pecatonica River Supply) offers his carved wood with just the barrel and ramrod grooves cut.
He offered the wood at the above price and at that time he charged $25 for the carving and barrel inletting.
This opens up several other possibilities.
His catalog says he offers the Kentucky style, Dueling style (that looks just like the Kentucky in his catalog), a Trapper style that is a full stock with a round (bag) end butt and a Hawken style which is a Half stock round end butt gun.
The Trapper and Hawken are set up for 15/16 barrels so either of them can be purchased in .50 caliber.
If you were really pinched for funds, you could order just the stock, cut for the barrel, in Walnut or Cherry for $25+$33=$58.
TOTW offers 15/16 pistol barrels in .36 thru .54 caliber for about $40 and a small John Bailes (Small Manton) Precussion lock for $70.
Of course there would be the cost of the breech plug, trigger, trigger guard, precussion drum etc but you could buy them as you go.
For comparative purposes, the Dueling pistol I'm making has cost about: $40 for the barrel/breech plug, $70 for the small Siler's lock, $18 for the trigger, $10 for the sights, $10 for the German Silver Trigger guard, $22 for the curly maple block of wood.
Track also offers the same style of pistol stocks.
Food for thought.
