Mark, I did that exact same thing, only for a temporary curiousity. I knew I was going to a bigger room, so I bought the 60's just before the price increase. Knowing I would use the 22's as rears (in the new future room) for better SACD music play. I placed them on-top, and off to the sides. You will gain some volume just from the increased drivers, but this would NOT be what you would want in 2 channel format. It didn't sound terrible, just not blended. The intergration of the speaker design, as far as crossover, blending, etc. will not match from a tonal standpoint, you are going aganist the "design" of the speaker, regardless of which one you use - use only one matched set of fronts. If you already have the 60's then the decession is already made. BTW, I know have the 22's as rears and the QS-8s as side surrounds, about 1-1/2 ft. in front of the listening position, running 7.1 I was dissappointed at first with 7.1, but after alot I mean ALOT of tweaking and changes, I LOVE it now. Just hard to find the right mix, but when you do, the direct rears, and side surronds give you the best of both worlds.
Sunfire amps & processor
Crown amp 2-SVS SS Maple Ultras, Axiom 60s,22s,150cc, QS8s