Well, one speaker I was going to suggest is the zigmahornets. For the most part you buy the 4" Merrill drivers from Two Bald Guys audio in Oregon and build the cabinets yourself. They are tall and thin, about 5" square and 5 feet tall, and while they don't shake the room with bass, the bass goes down to a solid 40 hz and is very, very articulate. Perhaps the best affordable SD speaker I've ever heard. My pair is just about done except for finish sanding and painting, but I have heard my friends' pair and they are wonderful. There are also people who build these for you, and at very resonable prices, and that might be a way to go too. You can also use the fostex fe-103 drivers, but at somewhat lower sensitivity. If you need more bas impact, an open baffle 10" Hawthorne Augie and a plate amp will be super easy to integrate, typically won't excite room nodes like a sealed or ported sub, and be fairly easy on the wallet.
Jim Rebman -- recovering audiophile
Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).
s.e.x. 2.1 under construction. Want list: Stereomour II
All ICs homemade (speaker and power next)