I'm a huge fan of monopods for anything telephoto and beyond. I've done enough event shooting that my arm just can't keep the lens up all day, so I've bought a monopod I can enjoy and use it a lot.

As far as low shooting, several thoughts:
1: I have an "fplate.net" floor plate (now sold through B&H Photo) that I've experimented with using as a ground-level tripod.
2: My new RRS tripod gets fairly low, though probably still 9" off the ground due to the handle on the leveling base. I think they're working on a new knob to allow the leveling base to sit lower.
3: RRS has a "ground pod" (aluminum, two-section, designed to be <2" off the deck) you might consider.
4: Wimberley has some flash bracket pieces you could clamp to the lens foot and place it on a towel/beanbag (http://tripodhead.com/products/flash...other-apps.cfm).