I have heard a few systems with mismatched centers, epos spic 2's with a polk center, cerwin vega 12" speakers with an energy center, and a few others {them 2 stick in my mind} and it was noticeable that something was wrong.... For the dialog it was OK, but when the fronts were lighting at the same time as the center, it was not pleasant...
Here's my thoughts...
First, with movies I can not imagine the need for $10K fronts? It may just be me, but tv and movies aren't recorded in a studio {a few exceptions of course like animated, language changes, and cut ins}, I have been on the sets of a few shows and a couple movies {outside providence, I got to meet George Wendt and Alec Baldwin {he was filming, George wasn't} and I can tell you first hand no matter what you spend on speakers to me movies don't sound super great...
NOW for music thats another story, I can see drowning your self in the material, closing your eyes imagining the artist is 6 feet in front of you for your own private concert, you can almost feel their breath.. I GET IT... I enjoy it myself... So if 10K get me closer I am down for it...
SO- to me a separate music system in a separate room or not makes a lot more sense, sure build a decent theater, but then get them $10K speakers and put them somewhere quiet, sit your chair in "that" spot {you know the one} and turn the volume up, disappear into a place so far away you forget that the cost of them speakers could feed a small starving village in Ethiopia for 7 days, lol...
But seriously, if I was spending $10K "or so" on a pair of speakers it would be these guys
SoundScape 8 , but I have heard the Ascend sierra towers with a pair of uls15 subs and I think I would go there first for around $5K in rosenut/dk cherry w/ ribbons....
BUT ANYWAY like others say, try it, if your ears like it, your good...