Currently stripping down my 2007 cbr1000rr (superbike engine going in), and it casually looks like the front end might fit the RC45
Upper fork 50mm, lower 54mm, fork distance 214mm... I think it might be a fit if I used the cbr1000rr wheel and discs etc. in the rc45 yokes.
Anyway, I might try it out of interest when the front comes out of the fireblade
-John