i don't trust those thermal sensors, generally don't change speeds when you want them to. most of the time i've found them rather worthless since u can't put the sensor in a good place or its not sensitive as u'd like. from what ive seen, they just run at medium speed about 99% of the time, annoying.
http://www.svc.com/fanandtemman.html
right there on the same site. i have 2 vantec nxp-201

in two pc's of course. 4 knobs, each does up to 18watts which means u can control quite a few fans with just one knob. i have 4 of the svc cheapo fans hooked up to my first knob alone, pretty sweet

i even hooked up the powersupply fans to it cuz i didn't like how loud they were. comes with everything u need, buncha cable adaptors etc.