Can you help me select a pre/pro?

It depends on the BluRay authoring. You should be able to choose the HD audio track, even in 2.0. Many of the BRDs I have (mostly opera and ballet, I must admit) have a lossless 2channel PCM track. OTOH, one can convert the 5.1 HD tracks to 2.0/2.1 if necessary.

The big point here is that all this should be entirely digital using HDMI output from the player to the processor, regardless of the number of channels.

That said, if you want the best from traditional 2 channel analog sources, like phono, an analog preamp with an HT passthrough would be a good adjunct to any MCH processor.

Thanks for your responses. I have been using the downmix option on my Sony DVD player (5.1.Dolby Digital -> 2 channel PCM) and then routing it to my Accuphase DC-61 DAC and then to my Accuphase C-250. I would like to do this in one box. Then I can work on my transition to true 5.1.

The other thing I am looking for is to take the 5.1 signal from my Motorola HDTV STB and processing it as 2 channel The 2 channel output of this box is weak and I would like to apply processing to the 5.1 digital output, such as DSP.

Again, many thanks.