Any question answered...

The mounting points are completely different - some manufacturers use identical calliper bodies with different adapters, but you can't use a front brake on the rear without at least changing the adapter. You can buy levers and callipers separately, which would allow you to have the right/rear set up, and some shops sell kits set up this way as an option. Also, current Hope master cylinders are double sided, so you can just flip them over.

mdcc thanks very much, informative and concise as always.

I'll PM Velocio about a a percentage of forum donations being direct debited to your current account.