gartrack used to make rwd escorts and orions, they used a cossie rear axel ( and ive seen another conversion like this) with either slightly widened arches or wheels with a wierd offset to get them under standerd arches. so it depends how much skinnyer your car is.
you could always go for a cossie axel with custom drive shfts (which arent that dear)
that way you can keep you standered body work (if your going for a 'sleeper' and you can keep normal offset wheels (look better in arches that way)

hope this helps (ps pm me some picks when mate, sounds like a beast