I also didn't like the brake lever being multipurpose and looked at the options from SRAM and Campy then I found a set of MicroSHIFT on eBay that looked like they might go cheap. I ended up getting them for something ~$30 shipped and gave them a try. I'm running 10 speed 5700 DR's and 6700 brakes, the Shimano stuff works great with the MicroSHIFT STI's. The MicroSHIFT lacks refinement, very industrial but gives good solid shifts with loud clicks to gives audio cues. I went to these from Claris 3x8 and much prefer the solid certain shifting of the MicroShift over the Claris. I do wish that MicroSHIFT made a set like this with rear exiting cables but their new series with that feature has the Campy type levers that stick out from the side, not like the 10 speed and below.

I founds these on a quick eBay search
Microshift 8 Speed Double Shifter Brake Lever Set Shimano Compatible | eBay
I would think you could find a set cheaper if you look and wait.