Let me preface that I have never heard the VP100 or the QS8s. However, I have done side-by-side comparison w/ the M22s and the M60s. Having done so I would have to recommend you focus on getting the M60s and then see what kind of wiggle room you have on the budget for the rest of the speakers. For example, you could get the QS4s and a VP100. Doing so would bring you to a $200 difference between the two setups, well worth the upgrade. Some would argue to keep the QS8s. This would only widen the gap by another $100. As far as the center goes, I have the VP150. However, I've read here that the sound advantage between the two is not considerable, rather it's a matter of how wide a field is created.
Truthfully, I know your position. I am sitting here looking at a spreadsheet that I created when I was trying to decide between all of the different configurations. I ended up actually buying both the M60s and the M22s so I could hear for myself. I really wanted the M22/sub combo to sound the same as the M60s, but I couldn't get there, even in the smaller theater room in which they now reside. Granted, I do not have as good a sub as you, but I still could not get over how much more full a sound that you get from the 60s. Even with a sub, there is still an audible gap there between the midrange and the lows covered by the sub.
Now, I suggest you take my comments with a grain of salt. Given the pairing w/ a better sub like an HSU, SVS, etc, the M22s might have better competed w/ the 60s. I can only judge with what I have to work with. In the end, even my budget-conscious wife couldn't agree to keep the M22s over the twice as expensive 60s. Regardless of what room we placed them in, we both agreed that the 60's just provided a more complete sound.
Sorry to add to the complexity of your decision. I just wanted to give some added input from the other side. Budget-wise, I should have definitely stayed w/ the 22s. I just had to make a decision that the added credit card pain was worth it to me to get a solid set of speakers that I wouldn't consider upgrading from anytime in near future.
Good Luck
