Included with the book, "Recreating the American Longrifle" by Shumway, Buchele and Alexander, is a nice profile drawing of what I think might be a Frederick Sell.
If I remember correctly that plan drawing shows mostly characteristics of George Eisters work. I believe that is just Bucheles idea of a fine longrifle, not a particular antique gun.
What kind of scaled rifle drawings are you looking for? This is what I do (and what I recommend you do) when I want a full scale drawing of a particular style of gun, or specific gun.
1) Find someone with a gun that I would like a drawing of.
2) Ask very nicely if it would be possible to make a full scale drawing of it.
3) Make drawing of it.
Where are there people who might let you make a drawing of there gun? Here on this board is a good place to start looking. Even if your looking for a specific very fine gun it is relatively easy to track down its whereabouts, and I have found that collectors are very cooperative when builders are interested in studying guns that they may have.
I always carry a soft lead pencil & a roll of butcher paper with me if I think I might see some originals that I might want a drawing of. Roll out butcher paper, set gun on paper, take pencil and trace the entire profile of gun, mark out on paper details like length of nosecap, sight position, pipe positions, trigger & guard placement, lock placement, lock moldings, length of tang, buttplate position, cheekpiece, carving placement any and all details. Take some small pieces of paper and take some rubbings of carving and engraving. Make whatever notations needed right on drawing. Take a few pictures. Only takes a few minutes to do all this. I keep all this info in large three ring binders and never pass up a chance to obtain more scale drawings of quality guns. What kind of gun do you need a drawing of I might have one. Regards, TC