You can find the original model for the USS RELIANT here:
SF ƒy[ƒp[ƒNƒ‰ƒtƒg ƒMƒƒƒ‰ƒŠ[
I do not know the scale though.
As for the NEBULA CLASS that is presented on ZOSHO's site, have you tried contacting him directly to se if he will email you a copy of the file?
EIther way, good luck with both.