I've seen them at Warn a few times. They are
HUGE!!! They won't fit on the Warn light bar. Even with a custom fabricated mount I wouldn't use them- they just don't look right with those big ass housings.
I've been seriously looking at the LightForce HIDs. They're a huge light, but they have a relatively shallow housing and a built in ballast.
I talked a friend of mine into getting them for his new F250 and he loves them.
Their U.S. site is under construction so you'll have to look at the Aussie one:
http://www.lightforce.net.au/images/HID.pdf