OK, here's the story behind my trial of Barcons/Paul Thumbies on a Origin 8 Gary bar.
I really love the Origin 8 bar on my Silvio and really love the barcon/Paul Thumbies on my conversion / commuter bike. I was thinking about trying the combination on my conversion bike, but was reluctant to do anything to it because I've been riding it back and forth to work so much. I wasn't really sure I would even like the shifters mounted that way with aero brake levers. When I bought the new bar for my replacement Silvio, I bought a second figuring if I ended up not needing on my conversion, I could probably sell it on down the road to a new Silvio owner.
Well, last weekend, I got to thinking about this project after a couple beers again and was looking at the remains of Silvio I. Shoot, I had everything I needed; I had an extra set of Shimano wheels, I had another set of barcons, derailleurs, check. I had to borrow some brake calipers from my fixed gear project. After I completed my inventory, all I needed was a 3' chunk of brake cable housing, a tandem brake cable and some new jockey wheels for the rear derailleur I was going to use. I tried the 155mm RPM cranks that Doug suggested on this build. I built it up over the long weekend and put it on the ground yesterday morning. You really can't tell from the pictures, but the TFT boom is bent where the handlebar attaches. It's not real drastic and you really have to look to see it, but I know it's there. I rolled out on it very hesitantly and was listening for any weird creaks or groans from the front end / fork. I also held my breath every time I rolled through a dip. I didn't ride it very far; just around the block a few times and run it through the gears. The shifters are great and are very handy in this arrangement. Shifting is crisp and easy. This was with old 8 speed stuff I had on hand, but I don't know why newer 9 or 10 speed equipment would not shift just as well. This seems to be another alternative you can use for Shimano equipment. I really like my Campy gear I have on the Silvio II, but will now consider piecing together a Shimano drivetrain because of the wider availability of wider range cassettes.
As for the Silvio I build, I will probably ride it another time or two around my neighborhood before I break it back down and consider it mission accomplished. I don't want to push my luck with that fork too much. The handlebar and all the gear will probably end up on my next conversion, which will be a hardtail based on a 24" kids mountain bike that I'm still looking for 650c wheels for. The rest of the components will go back from where they came from; the parts bin and my fixie project.
Mark