I haven't done one yet but have an action just waiting.....

Any 2-lever DST can be adapted, as you state, so the real problem becomes the fly in the tumbler. When the time comes to build my action, I intend to copy one of the flies I've seen on other sidelocks. Maybe you might try this same approach if no one else has a more definite solution.

I've found that the trapdoor arsenal trigger and grip layout & dimensions are quite thick and club-like when compared to a typical custom sporter. IMO particular attention should be paid to this problem when choosing a DST assembly and TG, and when contemplating the layout & shaping of the grip area of the trapdoor sporter. Most of the custom trapdoor sporters I've seen have appeared bulky and ill-shaped, and it's a shame because this action can be one of the most graceful when the shaping is done well.

I've found that it helps immeasurably to first make a full-size tracing of the barrelled action and then lay out several temporary stock shapes on it, to compare with other actions' dimensions & stock treatments.
Good luck, Joe

MerwinBray;
   The Rifle Shoppe websight only lists a single-set trigger. Do they also have a double-set assembly that I am missing? I am using a Hawken-style triggerguard on my project and a single-set kinda gets lost in all that room. Thanks.

Flatlander,
One of the things about Rifle SHoppe is to see everything they have, ya gotta buy the catalog. It is a little pricy but chock full of stuff. They are currently working out ballard actions and parts, both Merwin Bray ballards and the later Marlin stuff too.
I will try to dig out my current catalog and try to find the info for you. Could take a few! 
MerwinBray

This sounds like an interesting project for some of the trapdoor parts I have! Can someone give me the web address for The rifle Shoppe?
Thanks, Norm

PS....

for the davis trigger address go to the muzzleloading forum and look in their links.

while there, you mite really enjoy the forum. shoot a lot of flintlocks myself and thought i knew it all. after being on that forum for awhile did i ever find out how little i knew..

PS.. not really, just wanted to sound modest

tt.g

Were you to decide to go with a single trigger, that hawken gaurd can be reshaped so the trigger looks correct in the loop.  Its not that big of a deal to change the radius and attach a new threaded stud.
                     Steve

dws,

custers sporting rifle was at little johns auction  a couple of years ago. it was a trapdoor springfield with a cut down stock and a full length bbl.

bid $125,000 on it but, the bidding blew rite by me. ( thank you Lord)
at least i can say, 'i bid $125,000 on custers sporting rifle'

tt.g