As much i would love to see a QuadVee Hover, i think it may tip the scales little bit. It would be very fast machine. It could in theory depending it's weight class out run some machines it's size. I'm not certain QuadVee be allowed to mimic a Super-heavy (Hover) (51 tons or more). The closest Super-heavy hovercraft i am aware of is the Hexareme which is a 90 tonner, that goes 7/11.
A QuadVee(Hover) booting to 7/11 that's assault class QuadMech in vehicle mode would be pretty amazing.
FYI - Combat Vehicles over the usual 50 tons that are hover go from 51-100 tons are considered to be super-heavy combat vehicles I honestly doubt that a QuadVee would be allowed to be above weight of an standard Assault.
I'd think that a hover QuadVee should certainly be faster in vehicle mode than a wheeled QuadVee, but the hover equipment should be heavier. For example, let's say our hypothetical hover QuadVee get a +2 bonus to cruising MP in vehicle mode, but the hover equipment weights 20% of the total unit's weight. That means the QuadVee is paying 30% of its total weight simply be a hover QuadVee, which represents a serious penalty to the weapons payload.
I've built a min-maxed 50 ton QuadVee with 6/9 movement, XL engine, endo-steel internal structure and maxed ferro-fibrous armor. If built as a wheeled QuadVee, it gives 9 tons of weapons payload, with a 7/11 movement in vehicle mode. If built as a hover QuadVee as per the hypothesis above, we get 6.5 tons of payload at 8/12 in vehicle mode. That's not a lot of payload for a 50 ton mech, and I'd say a hover vehicle of similar weight would also have more payload. IMHO, I don't think the additional robustness of the hover QuadVee makes up the difference.
Ultimately, I think the writers' intentions were to create a
cool unit, not necessarily a
good unit. I'd say hover QuadVees firmly sit in the former category!