[icegreentea2]

There are some single layer units that can get up to ~90 of delta_T, but I don't think they're worth dealing with. As a sibling comment points out, you can stack TECs - indeed, you can buy integrated units with very high delta_T that are just pre-stacked TECs.

I think it'd certainly be fun to play with. Some bits of warning - most TECs are physically quite fragile. Not in the sense that you need to be super careful when handling them with your hands, but that heat stresses can totally wreck them. Do NOT hard mount both sides (hot and cold) to different materials - the differential thermal expansion on the two sides has a potentially of ripping your TEC apart. You may be able to get away with a hard mount (such as solder) on one surface, and some sort of thermal transfer material on the other.

Also warning, your hot side is hot enough to start doing weird things with normal solders, which might be the bigger limiting factor.