All,

After surfing all over to find a good way to mount a headlight, I stumbled upon Terracycle.  They have a universal mount that clamps onto any size tubing from 1/2" to 1-1/4".  See http://www.terracycle.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=T&Category_Code=Acmts. It was on the third page of a Google search, so Terracycle needs to get this thing exposed on more sites.  It's a bit pricey at $29.00, but it looks good and gives you almost unlimited options in mounting locations and angles.

I used it to mount a headlight at the front of our Longbikes Gulfstream.