Nes Suno , Mar 05, 1998; 02:31 p.m.
The Really Right Stuff people suggest the following: Gitzo G1564, Bogen 3232 swivel head, and the RRS B2-Pro clamp. I posted this in the regular Q&A forum: http://db.photo.net/bboard/q-and-a-fetch-msg.tcl?msg_id=0001BO. You will find additional suggestions by searching for "monopod".
If you're already using the Arca-Swiss style release plates, this is pretty much a no-brainer.