I have tons of ideas but I'm not sure what you want to do. How many channels of amplification do you have with your Krell amps? You want 2ch or 5,6,7,8... channels?
If you have the cash for Krell, they have an awesome 8.4ch pre/pro I'd salivate having in my setup...
I'm quite happy with my Emotiva UMC-1 pre/pro that I got for only $699 + s/h for Home Theater but I don't use it for 2ch, instead I'm still using the Rotel for that...
I have a pair of Klipsch Bella's that sound great with a stereo set up and then I use my other Krell amp that has three other speakers set up with it--I do not like the 5.1 HTS Krell that I currently have and am looking fo something that is a lot better and easier to use for a 5 speaker set up that will also go to a stereo set up for using cd's. Any idea's would be appreciated.