It wouldn't be that hard to do this tbh, and considering ram doesn't exactly throw out a lot of heat you wouldn't really need a powerful TEC.
If I was going to do this, I wouldn't actually place the TEC on the side of the ram at all, I'd buy a ram heatspreaders that were compatible with a ram waterblock and then also buy a copper heatspreader that was the same dimensions as the waterblock. Then I'd sandwich the TEC between the waterblock and the copper heatspreader and mount that on the ram heatspreaders where the waterblock would normally mount.
ie. exactly how Corsair was going to do it back in 2009:
You could replicate the above setup using a MIPS ram liquid cooling block setup, and using a copper heatspreader that sat on the ram modules and the TEC between the copper heat spreader and the MIPS waterblock. You'd also have to find longer screws to mount the MIPS waterblock to the ram modules - but it could be done fairly easily.
And as I said, RAM doesn't exactly put out that much heat, last time I checked, DDR3 ram averaged around 1W per 1GB. So if you used 2x 2GB modules, that's only 4W. Taking into acount extra voltage needed for higher ram speeds and you might be lucky to hit 10W. And for 10W heat load, you wouldn't need the most powerful TEC in the world at all, you could even get away with a much smaller and lower rated TEC.
To give you an idea, if you used THIS
TEC from CTE, which is a 40mm TEC and rated at 44W@24V/3A, and than ran it at only 12V - then with a ram heatload of 10W, and keeping the TEC hotside to 35C, the TEC would have a coldside temp of around -2C
And at 12V, that TEC would only consume approx 1.5A, so it could be run from a single molex from your PC PSU.
And if you wanted a lower TEC coldside, then you could use THIS
TEC and at the same 10W heatload and again running it at 12v, the TEC coldside would be around -6C