issue of speaker stands

There really isn't as much to this as you seem to imagine. Speaker stands need to be the right height, and they need to be stable. (They also probably shouldn't be resonant boxes, which is why getting rid of your towers is probably a good move.) As for the right height, that's less critical for rears than fronts. Beyond height and stability, go for visual aesthetics and price.

Where does one generally get them?

Ummm...have you tried googling "speaker stands"?

Seriously, every audio outlet I know of, both online and brick-and-mortar, carries them. Since it's tough to judge looks and stability from a thumbnail pic on the Web, I'd visit dealers in your area first (including the big-box stores) to see what they have.

Check out the following address for a nice selection that can be purchased online.

http://audioadvisor.com/store/categorylisting.asp?hdnCat=Speaker+Stands&sel=1&CategoryID=55

If you think you may eventually use them for two channel main speakers, buy nice "one piece" metal stands (like the 28" Target HR70 or the 24" HR60).

If not and they will be for rear channel use only then go by looks/price (inexpensive bolt together stands should be fine for the application).