For all those folks considering adding LiFePO4 to their rides. If you're buying loose cells with no BMS then check out this BMS over on endless-sphere: http://endless-sphere.com/forums/viewtopic.php?f=14&t=3345
It should be ready in DIY kit form soon at around $100 for a 16 cell (48V) system and can be easily expanded (or reduced) for other voltages. It has low voltage cut off on the discharge cycle and a charge management system (CMS) for the charging cycle. With this system you can use any charger that will put out >3.65V per cell - even just a power supply. The CMS takes care of ensuring each battery gets 100% charge.
Although they're designing this board for the LiFeBATT packs that they're going to sell to the e-bike world they've done a great job of making a board that can be used with any LiFePO4 cell and any charger. In fact, there was discussion about other chemistries - but I skipped those posts.
This is being done by Gary and Bob who are the guys that Don Harmon keeps mentioning in relationship to the LiFeBATT products for e-bikes.
This makes those Thundersky cells look more tempting...