Link's here:
1x 5 LUXEON Altilon SMD
A1SB-58505DH0xxxx0
www.lumileds.com/uploads/657/DS175-pdf

But with 1,500lm at 16.9W, wouldn't it be 89lm/W ?

If you construct the battery as case for replacable 18650-cells, costs would be fair. Especially if you think about he amaount of YinDing/Magigshine users who will be interested because of the compatible DC5521 plug.