I'd hate to see your power bill.
I don't dispute the quality of the performance of these speakers, as you seem to be quite enthralled by them.
Perhaps you could consider using these for your fronts and finding alternative speakers for your sides and rears. These alternate speakers are really more support based anyway and perhaps the Kappa's are being "wasted" on the intended purpose and location in some regards?
I got into HT for a while, ended up with 5 Wilson W/P 5.1s, but in the end, I didn't think the rear ones were really being put to good use - especially more so since I am not a movie guy.
Just a thought and it sounds like it may address some of you issues between amplification, speakers, and room fill. Part of me thinks that you are being forced into sub quality amps in keeping your speakers and based on the budget, and if this is the case, I suspect you will be disappointed after spending the money and not getting what you want.
Again, I would start by going to Guitar Center and renting the amps for a weekend, tell them how much power you need - if its 2000+ watts per channel, they'll have it. It will end up being the cheapest way for you to determine if you can go "pro level" amps.