A number of forum members have used 3 RC-7's (RC-64 predecessor) across the front with excellent results since the timbre' matching will be spot on.  I cannot imagine it would not work well and I am sure with all those woofers your bass response won't suffer much if at all and you have a subwoofer as you stated to boot.

 It would certainly look very impressive, post pics when you do it!

That would be an awesome front setup.  I believe I read about ones rotating the tweeter horn 90 degrees when standing an RC-7 upright so that the horn is focused correctly in that positon.  I don't think its too difficult to do.

Cant rotate the horn since it is one molded piece of the baffle. I mentioned this is his other thread.  

We have had some people do an RC-64 in L/C/R configuration.  It should work extremely well. 

 I had thought of designing a shallow profile version of this for "on the wall" applications with flat panel TV's.  The cut off would be much higher.  Depending on the box it might be 125-150 Hz but this isn't an issue if you use a good sub.   

 what's the dispersion pattern on the horn? The RC7 could be removed and rotated 90 degrees. Can you do that with the RC64 for tower configuration? If not, is this really a wise move?