As mentioned above, it's relatively easy to do assuming you've got preouts for the main channels on the receiver and get a preamp or integrated amp with a processor loop. (However, I don't think that it's necessary -- or necessarily recomended? -- to run two seperate runs of speaker cables, from two seperate amps, into the same pair of speakers (forgive me if I misinterpreted)).
When set up, it will essentially be a 2 channel system with a parallel add-on for processing and 3 extra channels (or more, if you want) of amplification when doing HT. It's vaguely counter-intuitive at first, so forgive me if I am overly simplistic, but it works like this. The two-channel system is essentially stand-alone when in use: CD (or source of choice) to preamp to amp to mains, season to taste and go. Next to it, or at least next to it on my rack, is the DVD (runing digital into the processor section on the receiver) the reciever and, for good measure, a VCR. The amp section on the receiver powers the center and surrounds, while the mains run from the preouts on the receiver into the processor loop in on the preamp (which then sends the signal to the main amp and onto the speakers, of course). This way, the mains never see anything other than the tubed preamp and the Bryston and, when listening to music, the HT gear is turned off and minding its own business. As far as I am concerned, it's the best of both worlds -- you can have a reletively high end (as high-end as you want, really) two channel system mated with a relatively cheap HT receiver for all of the 5.1 channel whistles and bells without having to worry about trying to find a HT processor that can do both movies AND music well.
Down the road, you could even add on seperate amps for the surround and center channels (again, assuming that you've got preouts on the receiver for them). That said, if and when you get that far down the road, you'll likely be looking at ditching the reciever anyway and going full seperates for HT as well, which, for my money and usage, seems entirely unnecessary. But that's me.
Finally, if you're in the mood for consolidating even more,
if you've got a DVD player with both digital and analog outs (which you almost certainly do) you could run the digital into the reciever and the analog into the preamp CD input and have the DVD do double duty. I tried this just for fun and found that, for music, the onboard DAC on the DVD was far superior to the DAC on the reciever. (I run the DVD analog feed into the AUX input on the preamp). Sure, I prefer the CD player to the DVD, but what the hell, I had to try it....
As for recomendations (yea, I hadn't forgotten) I'd have to agree that you could probably find a nicer intergrated than seperates in your price range. There was a Classe CAP 101 posted just today for $1,195. I don't know integrateds well enough to offer any pointers (or even whether the Classe indeed has a processor loop) but, as with anything audio, would encourage you to try to listen to as much as you can first. The recomendations above are an eccellent start, and you can rest assured, as long as there's a processor loop, that it will mate with the HT gear. Focus on the music, and just pick the one you like the sound of most. Best of luck.
