I may also employ this if I get a pyxie frog, as it will be less annoying than a bulb that needs to sit on top of the cage and be in my way when I want to feed it.
Also curious to know if a reusable product called "water pillows" can be used by roaches. http://www.petco.com/product/12128/Zilla-Cricket-Water-Pillows.aspx For instance. These could be hung by clothes pin so as to touch the bottom allowing roach to climb and suck on it while not gathering excessive fecal matter.
People have tried the water pillows, and they're good for a while, however they'll eventually get pretty nasty and need replacing. Far more expensive than buying water crystals in bulk, $6 at a Sears type store will get you much much farther.
The problem with using the UTH with a plastic tote is that the UTH's are designed for animals, and as such they have far fewer safety mechanisms built in to prevent a short in the circuitry thus leading to unintentional excessive heating that can melt through the plastic and most likely kill your entire colony. A friend of mine had a reptile UTH for his ball python, it shorted and burned a hole into his carpet. Luckly his snake was unharmed. The human heating pads however are much less likely to short and overheat (and the one I have even costs less) than the UTH's because they're designed for people. That's a much larger lawsuit if they screw up, so they take safety more into account.