I did some measuring and some reading, and here's what I've come up with:
The gutters (that run front to back) on our H2s are 64.5" from center to center. The safari racks, and all others that I've been researching come in a maximum width of 54"...not going to work to mount to the gutters.
The other option is to mount to the cross-bars. I'm not a fan of this because that rack would be WWAYYYYYYYYYYYYYYYYYY up there, so I may have one custom made.
Here are some links to racks that can be cross-bar mounted. I've talked briefly with these companies, and they can't GUARANTEE that their racks fit, so caveat emptor.
Kelley
http://www.yakima.com/products/dynamic/8007080_6.html
http://www.yakima.com/products/dynamic/8007070_6.html
http://www.thuleracks.com/thule/prod..._id=11&sku=840
(thule racks actually have a "fit wizard" for your vehicle and show needed hardware and mounting brackets. This one definitely fits the H2)
http://www.4wd.com/default1.asp (search for roof racks, you'll see a listing with links to each. I'm investigating the Wilderness racks in a 54" width)