Take a look at EAD.
How about Anthem AVM2 or AVM20, or Classe SSP-30 MkII. Also, if you are happy with your current home theater processor, you could just add a two channel preamp for music, like an Audible Illusions Modulus 3A, BAT vk-3i, etc. or another model with a home theter pass through. Good luck with whatever you choose.
I would suggest the Proceed AVP if you want to go with one box.
To add a dedicate audiophile grade pre-amp to use with your current amp and speakers: you have to POWER OFF your amp, unplug the interconnect of the L and R ch. from your HT processor, and plug it into the L & R ch. output of your audiophile pre-amp. Power up your amp, and there you go. This configuration assume that your source (DVD player or CD player) has already connected to the pre-amp thru another set of cables.
You will save a lot of space and money for a complete second system. Hope this help.