Brucer, I've tied them in rusty brown shades. Danville Chenille has a couple of chenille colors that would fit that description, and I've used rusty/ red-brown dubbing. They're not colors I would use a lot, but they can be good sometimes.
Red is not a color I use much, but do like a dark red bugger sometimes. There is a fly from New Zealand I saw in a magazine article, that resembles the Woolly Bugger. I believe it was called the Fuzzy Wuzzy, but not sure. It was tied in segments, alternate sections of red chenille & black hackle, with a tail of hair. I don't recall the hair that was used, but I've tied a version using dyed black fox tail, and a version using black ostrich herl in the tail. Bass seem to like it.
White buggers are always good to have in a fly box & I've experimented with all kinds of hackle & body color combinations. You can get a crazy as you like, but frankly basic colors still produce he best for me. As far as white hackle, I like it with black & pink bodies with white tails, and of course all white. These combinations work well for bass & panfish. Don't how they would be for trout, never tried it.
I'll add any type of weight to buggers, lead wire, beads, cones, bead chain & barbell eyes. All work.
I rarely tie anything smaller than a size 8 but you could certainly tie them smaller. I have tied them as large as a 2/0. There really is no limit if you can find the materials to match the hook sizes. Size 2 & 4 are probably the hook sizes I use most since I primarily am a bass angler. I've tied them in white & chartreuse & white on size 2/0 saltwater hooks with Striped Bass in mind too. Tied with ostrich herl in the tails, they can be quite long!