For those interested we have successfully installed a Yamaha DSP5D:
PM5D, PM5D-RH, DSP5D, DCU5D | Mixers | Products | Yamaha Pro Audio
This is essentially a rack mounted PM5D-RH minus the control surface. It makes more sense for us to use computer control as we don't have the room to safely house a large control surface.
Inside it we've installed an 8 channel 96KHz digital I/O AES card with sample rate convertors, through which our jukebox, DJ decks, and DVD will input, and our stereo will output into the digital crossovers. There's also a T-diff card that hooks it into the digital recorder.
We didn't expect a noticeable sonic improvement but ended up being blown away by it. Sonically it's so different that we need to re-calibrate the speaker balances on the crossovers. Previously we had only one minor EQ tweak at 100Hz, now we're running ti absolutely flat.
On the monitors we had 4 parts of EQ round the crossover frequencies, these are also now flat, and once again it's possible to 'rest' to mics on the monitors without anything feeding back (I know the goes against everything I've learned to fear LOL). The removal of the monitor EQ has dramatically increased clarity and volume in the monitors (although volume was never much of an issue).
The DSP5D also comes with some high quality FX and emulators.
Channel wise there are 48 pre-amp XLR inputs with AD convertors and, unlike the DM1000, the gains on these are all electronically adjustable which is a big boost. Following on from there are 24 bus channels and 8 matrix busses. There are also 4 stereo inputs which we have linked up to our digital I/O card. There are 8 FX processors to play with, and dozens of FXs. Finally there are 24 OMNI outputs which we'll use mainly for monitor output. We were considering upgrading the monitor outputs to full digital, but there doesn't seem to be much point now.
All round clarity is enhanced through the FOH, and the lower frequencies are much better represented. The whole thing sounds a lot punchier and more powerful. IMO it's impossible to tell whether it was analogue or digital now, just that it's incredibly high quality.
The first gig with it is this Saturday, but it might take a few weeks to really start to exploit it's full potential.