Puerto,
I would disagree with the statement "there are no surround sound pre-amps on the market today that employ quality DAC systems." I think that the DAC's in my Anthem D2 are very respectable. As I said in my previous post, I prefer the sound of the DAC's in my modded SB2, but considering that I've spent around $3000 on those mods, I would hope that they did sound better. It's a matter of personal preference, and I'm sure that the average "phile" would be more that happy using the DAC's in the D2.
Over the years I've owned a few surround processors and have had the privilege to audition many more; some in my own system. Having owned both the Anthem AVM2 and AVM20, I can say that they both have respectable DAC's. I prefer the AVM2 over the AVM20; more "tube" sounding. Having recently had the opportunity to audition the Denon AVP-A1HDCI, Marantz AV8003 and Integra DHC-9.9 processors, I can say that they are all respectable processors at their price points. The Denon was the best of the bunch, but at 3X the cost of the other two, it should be. The sleeper of the group was the Marantz; very good sound for the money, but the interface and remote was a disappointment.
If you really want to go down market, the Outlaw Audio 990 is a real bargain at $700! It's not in the same league as the big boys, but one hell of a bargain. I thought that the buttons on the face were cheap, but considering the price, I can't complain. Also, they are coming out with a new model, the 997, that will have all of the latest formats and HDMI switching for $1400. Outlaw processors are based on the same designs as the Integra units.
I've also had the pleasure of playing around with Lexicon, Theta and the big Mark Levinson processors; all very nice and I lust after the ML processor. Incidentally, both the ML and Anthem D2 use Gennum video processors.
As for the Benchmark DAC1, I would audition it before committing to a purchase. You can order it from Benchmark and they give you 30 days to return it for a refund. I ordered one and thought the presentation was a little to forward for my taste, so I returned it. I'm currently using a MHTD Paradisia Tube DAC in my office system.