Looking for a trapdoor

[LongWalker]

Anyone have a trapdoor they are thinking about swapping off? 

Playing with this Krag infantry rifle has brought me to the realization that "quitting trapdoors" has much in common with "quitting smoking".  After a 12-year trapdoor hiatus, I'm once again in the market for a trapdoor.  Ideally, I'd like to find a cut-down 1868 or 1870, with an eye toward building it up like the 1866 sporter I used to shoot occasionally as a kid.  I would also be interested in an unmodified infantry rifle (with no intention of modification).  Bore condition is my primary concern, as I want a shooter.

Meantime, I picked up a copy of Hosner's The .58 and .50 Caliber Rifles and carbines of the Springfield Armory, 1865-1872, and started looking for Barker's "50-70 Shooter's Handbook".  Any other titles I should be searching out?