yes the center is not the greatest, especially to match the 836's. i would not however switch brands.
look into the profile cc908, it is a 3way, the tweeter is very similar to the chorus. this would probably match better than a paradigm.
i have a pair of 807 as my fronts and i need to get a center. i'm kinda in the same boat as you, i dont really want the cc800 as my center. but i'm thinking of buying another 807 to put in the center that way i will have 3 matching speakers across the front.
but i am assuming you cant fit a tower in the middle to match your l/r. besides it would be hard to find a single tower for sale.
check ebay there is a cc908 for sale right now, you can probably get it cheap. i would buy it if i had the money...