On the DAC side, look at Beresford DACs. They just released the 7520, which has USB input, but their 7510 with optical and coax inputs is still available too. Reviews are very solid, and there is a lot of discussion of mods for the DAC at the Art of Sound forums (designer and seller of the Beresford also posts there a ton). If you don't need USB input, MCM is also selling a rebadged eariler version of the 7510 for as low as $79 with a regularly appearing coupon code (google $79 DAC and you will get to a thread on the DAC which should have the most current code).
Amplifier wise, how much power do you need? There are some pretty amazing Class T amps out there at a range of prices, if they are powerful enough for your needs. Parts express has a rebadged version of the original Sonic T-amp for $40 or so. There are a number of T-amp reviews around the internet. Googling T-Amp shootout will get you to these. Trends and Kingrex both seem to score well in these.
If you need more power, I recommend a rebadged Emotiva BPA-1 that's made by Dayton and sold by Parts Express. I have a BPA-1 and love it. A very versatile amp. Can be bridged or run two channel. Has all the adjustments you'd need to use it as a subwoofer amp, and a volume control.
AudioSource 100 is another versatile amp that you might want to consider. Has multiple inputs, volume control, can power 2 sets of speakers (for multi-room set-ups for example). 2 year transferrable warranty. It is bridgeable as well. I have one of these a year ago that I haven't gotten around to selling yet. PM me if you might be interested.
All these are for sale new, with warranties. The used market is an ocean of possibilities that I don't have time to wade into right now.