Three weeks ago I bought from Dive rite express a 10W HID:
Dive Rite HID Lighting Systems...Head, Bulb, Canister, Battery, Charger, Guide
Very straight forward to do ,
You do have the import duty (£60 approx) but even with that a very good price. even with this still cheaper than from the UK It only took four days from ordering it to delivery
If you are in the states even better with the pound/dollar exchange rate at present.
I have used the light and it works very well the slim line battery pack is also very nice, hardly know it is clipped on. If you buy it at the present you even get a nice free case to carry it in.
Andrew.