Look for older steel risers. I've got two pairs of Bontrager Crow-Bars in steel (one yellow and one black) that are both 7/8" clamp. They have a goofy little crossbar in between, but otherwise are pretty cool. Look around, you'll find something similar.

The cro-mo DMR Wingbars are also 7/8" clamp. They have like 3.5" of rise and weigh a TON though.