Never thought about making an R10 (r11..) OD standalone, behind a standard trans! Good idea!
I didn't meant to argue "in favor" of the R10 vs R11, it's just all I know :-)
I really like my OD unit. Yeah, a T4 or T5 would have obvious advantages, but it wouldn't have the character of a 3 speed plus OD. I like the OD! If I wanted a !@!@#!! new car I'd buy one!
Who wouldn't want this setup?
http://wps.com/AMC/1963-Rambler-American/images/lm8.jpg(Photo is post cleanup, pre-customization :-)