I've made two modifications so far (more to come...)
the rollei sl 66 is great, at it has a bellow system so you can fit odd lenses on it....
below two exambles;
first two: old projection petzval lens (Suter "ki" lens.)
third: old Lancaster landscape lens---
Awesome! I have the custom mount that allows Copal #0 shutters to be mounted on my SL66 and am currently scouting for interesting lenses to use with it. gadolfi, any portraits taken with that brass wonder??