The Manfrotto 055XPROB can be put right down on the ground, and it's more than up to the task of holding your gear. Indeed, it works great with a gripped 5DIII plus the 180 macro with flash on rails on a ballhead -- just be prepared to weigh it down if you need to extend the setup past its tipping point.
(I actually prefer its older cousin, the 3021BPRO, for on-the-ground work. I've got both. The 055XPROB is great; the 3021BPRO is even better.)
Cheers,
b&