Sorta hard to describe where he is...basically, he is near the zone to the
live side of LG. Best way to show you where he is is have someone lead you
there or look at a map of UG.

Dunno how exciting it would be for your guild to hunt there though. Maybe
if they kill all the frogs while getting there. His placeholder and his
spawn time is 15 min. I truely believe he only spawns twice in 24 hours
though...if even that...sometimes I think he only spawns once in 24 hrs. I
camped that spot for 48 hrs straight practically and finally just traded
some stuff for the leggings. I heard some people who were after the leggins
have to camp over a week to get em. BTW the legs are the rare drops. I
collected up to 3 arms while camping him in 48 hours.

The reason why I say that this spot might be boring for a guild raid is due
to the fact that it is usually camped...by ppl who usually can camp
solo...(i.e. druids, wizzie, necro, shamans, etc) The arms are sought after
by the int casters and the leggins are sought after by all the wis casters.
On top of that...it's a pretty boring camp.
To camp it solo...you must be at least 36. A small group (let say less then
5 ppl) of 25+ can handle that spot easily.

Might be best to have your guild do the entire UG to liven things a bit.
Making a round of all the name spawn area might be fun.