We got an email over the weekend from Mik Efford, who's in the process of building a bamboo bike frame (and documenting it on his website, Bamboo Bikes). Right now he's working on brake mounts and hit a snag. As he puts it, he was: 

"almost done...until I get to the rear brake bosses. I thought I could use these guys which I stole off my Voodoo Wanga MTB:

 

But alas the offset between the screw holes and the pivot posts is too great. It'd be awesome if there was a range of these available with different offsets so they could be fitted to custom frames with differing seatstay widths." 

Problem Solvers doesn't make anything like this (yet?)...anybody got ideas for Mik? Leave 'em in the comments.