I know this is quite what you are talking about, But in looking for an option to bar con type shifter for the front mech, I did find a Huret LEFT side clamp that fits over the right side braze on boss. This will NOT work on a Campag bolt! Simplex Huret and EVEN Brit bolt will.If this is of use to anyone Email me Crumpy6204@aol.com I will gladly send it to you along with two Huret double downtube cable clamps FREE! . Cheers John Crump OldifyoucantsellemgiveemawayBrit Parker Co USA