So I've been thinking that Shimano Octalink road cranks (e.g., 5500-series Hollowtech 105) would be great for fixed-gear use. They're stiff, available in 165mm crankarm length, and giving proper 43.5mm road chainline with a 109.5mm bottom bracket, would give proper 42mm chainline on the inner ring if used with a 113mm bottom bracket. However, I've only been able to find Shimano Octalink bottom brackets in 113mm if they have the V2 spline, which is not compatible with 105/Ultegra/DA groups.

This scheme would work with Sora or Tiagra double cranks (which use a 113mm V2-spline Octalink crank) if used with a 118mm V2-spline Octalink crank. But I'm mainly interested in the 105 and up.