I have an 18x24cm plate camera, even if not of the FKD type.
I bought a couple of cheap "clip" frames on IKEA, and use the glass and backing (one on each side) as "backing" for the film. So open the holder, insert film, insert glass, close (that side of the ) holder. Repeat as necessary. Works just great.
The 18x24cm plate holders are generally smaller than film holders, but it might still be possible to build a new back for "standard" film holders. This is on my (growing) "to do" list...
It's heavy, but not unreasonably so. Not significantly more than most folding 8x10" cameras - like a Gandolfi.
18x24cm film is still (fairly) easily available form Germany, but even there 8x10" is taking over as the market shrinks. Retrophotographic has MACO UP100 in 18x24cm.
But can anyone tell me where I find 30x40cm film for my Russian plate camera?