I'm surprised this hasn't been mentioned here before, but has anyone tried the Wilson Steam 99S or Steam 105S?
They have a unique string pattern - 16x15, which means they are the first racquets to have more mains than crosses. The pattern is meant to amplify the effect of poly strings, adding about 10% more spin. These racquets have been around since about March. These have been the "hot" racquets this season, but are definitely not for everyone - some at Wilson will even admit that they are not well suited for advanced players.
Last night I spent about 3 hours hitting with a new "S" racquet, due to be released in September. It's called the Blade 98S. This one has an 18x16 string pattern, so it feels much more like a traditional racquet - I play with the Blade 98 16x19, so I was quite anxious to try this one.
I have to say, imo, this is a much better racquet than the Steam "S" racquets. Much better feel and control, but still definitely upping the spin potential. If you've ever hit with the regular Blade 98 16x19, this one felt more flexible, and is about 0.4 ounces lighter. I didn't care for the lighter weight at all, but that can be fixed easily with some lead tape. I'm not sure if I liked the extra flex or not - I strung these for my Wilson sales rep, and was asked to not use my usual 49/46 pound tensions, so that affected my feel a little bit.
I also strung these up with a soon-to-be-released string called RipSpin - Wilson's answer to the RPM Blast, but at a much better price. It definitely felt a lot like RPM (I've used gut/RPM for the better part of the last 2 years), but slightly softer. I strung one of them at 58lbs with full RipSpin, the other at 60lbs with gut/RipSpin.