I've posted recently a few times in the Novantrone forum, saying much the same thing.
My situation is very similar to your wife, quick onset and rapid accumulation of disability, other than i'm 35, have had (DX'd) MS since Oct 05, and have just completed 2 years of Novantrone (or Mitoxantrone, as it is known in Australia).
After my first couple of infusions I didn't do much, other than feel sick for a couple of days, and spend a lot of time sleeping for most of the week. Certainly, not quite to the degree your wife is showing, but I am fortunate to be one of the lucky few who rarely, if ever, suffer from unpleasant side effects or reactions to medication. After the first couple, even the reactions I was having just about disappeared, only minor fatigue ( I was able to return to work, while i was working, after taking only one day off) and the nausea was controllable with a couple of anti nausea tablets.
Everyone reacts very differently to the chemo, some get really knocked around, some have a relatively easy run like me. Your wife's side effects may just be how she reacts, and hopefully it'll get a lot easier for her, but either way, you should definately be in touch with her Neuro and the Dr.s at the infusion centre, it never hurts to be to carefull.
Incidently, I never had the feeling it was a miricle cure, or quantifiably made me feel better, or improved my physical condition, but I'm not a Neurologist or an MRI machine, and My Neuro saw significant and considerable improvement between my pre-chemo MRI's and the post-chemo MRI's.
I wish you the best of luck in future.