Ended up pulling on Panavision's 45mm slant focus lens the other day. So much fun, but I had to ditch my FIZ and the mattebox (sadly no clip on retainer ring for that lens) and pull off the barrel while the op controlled the slant. It worked for the shot, but was a little messy.
Has anyone had any success hooking up a motor to a slant focus? This is such an oddly specific scenario, but I'm sure I might run into it again with this DP. I was thinking you might be able mount a focus motor in the same manner you would a zoom control- directly onto the lens so it shifts as the lens swings without losing contact.