Thanks, yet again. Yeah, I was just reading the link you gave me, and the schematic doesn't look too difficult to implement. A bit more work, but, hey, if I didn't like tinkering, I don't think the Arduino forums were the right place to be in the first place 
Anyway, the opamp and the multiplexer were really cheap parts (both were in the 0.20-0.30€/piece category), so I ordered a few of those already. The rest are just a few resistors, caps and a pot that I probably already have. I have a few pieces of breadboard lying around so I'll first build it there and see if I can scourge up something more permanent after that. I'll probably first try without the amp/multiplexer (simply because they take time to arrive) and see if I'm able to do without.
I just wish there'd be something as simple as a TMP36, but with more temperature range... well, anyway. Thanks for the pointers.