Thanks for the picture. I was thinking along the same lines as you. I wanted to improve the intake system without risking water ingestion. I think the stock air box is fine, it's just the tube that looks ineffectual.
What kind of lift did you add? How is the handeling after the lift. I am thinking of adding a lift and tires too. Check out this site
http://www.t2hummer.com/T2Hummer/WHEELTIRE.HTM
I like the B5 and C3 wheels. I am wondering if a super charger is inevitable after adding bigger wheels. The H2 feels slow with stock wheels. I have added headers and a Corsa exhaust to try and add a little power, but don't feel much of a difference.
By the way, have you posted a picture of your H2 after the lift and new tires?