I know a few have done it, I just did it myself and I found the other examples in the tri bike on the cheap thread. So who has done it and did you find any problems, or did you love it? etc. etc. etc.

Its Common for Time Trial bikes to put bar end shifters in the front end of the aero bars.
so since those like Pauls Thumbies require a set of bar end shifters to be purchased first,

try that before buying the thumbie mounts..

I have a profile for speed old aero bar set, It's 1 aluminum tube,
bent to be bullhorns and aero bars,
in a bin around here now,
they offered a bracket to mount downtube levers,up front,
right at hand, so while hammering the course, the racer could change gears
without coming out of the aero crouch.