$$$$ Chargers
Are you guys POSITIVE the same charger can be used for all type of lithium batteries, or just making a guess???
The LiPolys have different voltages and charging profiles from the other types of litium cells. Chargers made for LiPolys say not to use them with other types of cells, and the literature with the cells says not to use chargers made for other types of cells (including LiIon cells).
If what the manufactures says is true, and my guess is that they know what they are saying, then any money you save by building a cheap charger will be wasted on ruined LiPolys. At ~$9 a pop for single cell, it won't take ruining many packs to have bought the best charger there is out there...