Wayne, Convertng an 8x10 to 4x10 is no problem, if you have some basic woodworking skil ls. Especially if your bellows are in good shape. A while back, I converted an old Kodak 8x10 flatbed camera to both 4"x10" and 6x 17cm formats by building a set of new ground glass backs. I am currently convert ing a pair of Calumet "405" 4x5 view cameras to 4"x10" and 7"x17" panoramics, w ith full movements. The trickiest part of the project is the film holders. You can buy new 4x10 holders from KB Canham, but I understand that they are really expensive. I have found that I can convert certain wooden graflex 8x10 holders to 4x10 by spliting them down the middle then trimming and glueing. Same thing goes for converting 5x7 holders (easier to find, less $$) to 6x17cm which uses c ut lengths of 120 roll film, or split 5x7 sheet film. I'd be happy to give you a hand in you project. I find both 4x10 and 6x17 quite exciting formats to work with.