Troute upgrades them with XML U2 LEDs and a new driver for about £75. They then put out a geniune 1000+ lumens. If its the mk1 you have and you are a bit handy at soldering etc. you can do the upgrade yourself for even less money.
It always amazes me why people pay so much for Hope Vision 2's on ebay. They are very old tech now. The mk1 is only 300 lumens and the mk2 is 480. You can buy all in one (no seperate battery pack) commuter lights with the same sort of power and burn times brand new for the money that second hand vision 2's go for on ebay. Alot of people sell the mk1 qouting the specs for the mk2 too and claiming them to be almost new, they stopped making the mk1 over 4 years. I know all this because I've been trying to pick up a cheap mk1 to do the Troute upgrade on. I've been bidding on one recently with no proper battery, it comes with some unknown cells that the seller claims could be built into a battery pack if the buyer can solder. Hard to make water tight though. That one is already up to £50 with 14 bids and a over a day to go. Unless all these people want to do the troute upgrade they's be better off buying one of these:
http://www.chainreactioncycles.com/Mode ... tAodkDoAew