| Agree with the previous poster (and others with the same point). The H4 "100th level characters" was really just an eye-catching marketing tag line.
The module description made the key assumption that: no one over 29th level got any more hit dice, attacks, abilities, saves, or spells of any sort. That was a pretty ridiculous misreading of the 1st Ed. rules as written (which simply didn't address higher levels one way or the other). So as fas as the H4 text was concerned, 30th level was rules-wise identical to 100th level, which was pretty absurd.
I'm not much of a fan of this module, but I think if you were to convert it for 30th level PCs, you might have an easier time making things sync up.
__________________
Allowing "New Magic Items" is a rules variant (DMG p. 214), so please put them in House Rules.
Like the DMG says, "the formulas only provide a starting point". | 
And yet another word from our sponsors
