I modded my iliad v2 with two batteries(about 2X capacity of the original), the protective circuit of the battery is already inside the iliad, what you need is to find two LiPolymer batteries and replace the original ones. the batteries are connected to the protective circuit via wires so you just have to solder the wires onto the corresponding electrodes.
the two batteries cost me 60RMB...about 6 Euro...I am in China
