I'm not sure I would want to try to buy anything in production quantities from any of the suppliers listed below, but they have a good smattering of strange and unusual bits and pieces.
Also known as Web-Tronics. A good collection of test equipment and tools, both name brand and some very affordable Chinese stuff.
Marlin P. Jones Associates:
Inexpensive test equipment and tools, plus closeout components at good prices.
BEWARE: As of 2012 they have gotten in the bad habit of making untrue claims about their products. If it seems to good to be true, it probably is.
Mostly closeouts and one-time buys. Good selection of unusual parts.
HSC Electronic Supply
; Located in the heart of Silicon Valley, it's hard to define this one. they may not have a lot in the way of components, but they carry a constantly changing assortment of high tech stuff. Much of it is surplus from recently defunct dot-coms.
American Science & Surplus:
A very quirky source of odd bits and pieces. If you don't need it, they're sure to have it in stock!