Have you considered Elac bookshelves or floorstanders? Ribbon tweeters will give you nice, sparkly highs that won't be edgy thanks to your MC. The ProAc K1 is also a nice, large standmount with a ribbon tweeter. Monitor Audio PL series might be out of your price range but the Gold series is highly rated. Of course if you were willing to stretch your budget a little, the Joseph Audio Pulsar would certainly be worth a look. I've listened to the B&W 805D after owning CM5s for years and honestly, they were nice but I didn't hear the step up in performance I was expecting coming from the CMs. With the size of your room, I think your money would be better spent with the best standmount you could swing plus a subwoofer that you can place in an optimal position in the room. And, of course, extensive room treatments. I was in your shoes and I wound up buying a used set of Magico Mini IIs here on Agon. I do not regret it.
