John,
I have 12 of these clamps: Rockler Sure-Foot Plus (Rockler # 30921) and Rockler's 48" zinc-plated pipes (#26275); they sell them separately. The clamps are in like-new condition (once I wipe the dust off) but the pipes have some glue runoffs and occasional tooth marks where they were really cranked on, but not enough to interfere with the clamps function; all appear to be dead-straight, which is a big benefit of pipe clamps. Coining another NCWWer's quote, they'll last a lifetime if you die when you're supposed to.
On a per clamp basis, they cost me ~$32 each (+ shipping); I'll sell them individually for $26 each including shipping OR $22.50 each if you take them all. If you're interested, PM me back. Thanks,
Russ