gswitz
The UCX gets hot. If you want something for a rack, get the UFX. I sit my UCX next to a quad mic pre from RME on top of my compressor beside my desk.

UCX's get damn hot!
FWIW, I've got one in a 4U rack with spacers, a stereo pre and a compressor above. You could have boiled coffee in there till I stuck a 12v computer fan on the back. I run it at 4.5 volts to keep the noise down - and now things are cooool. But bang for the buck, those RME's are hard to beat!
David

QuadCore
Wow.  Awesome.  Thanks for all the ideas and tips, guys.  There's a lot to consider here. 
 
There is also one constraining factor - I am going to want to have two hardware devices connected through S/PDIF, so unless the X32 has a S/PDIF card or module option it  is off my list for now (Damn).
 
The RME, 828x, and the UAD Apollo all have S/PDIF and ADAT ports -
RME and MOTU say their units will configure for 2X S/PDIF I/O (by configuring 1 ADAT port to S/PDIF format) - not sure about the Apollo yet.  Anyone know which interface works best with two S/PDIF I/O channels running?
 

Afaik there's no spdif option planned for the x32.

Adat is a light pipe connection, keep that in mind, you might need to convert.
The motu adat ins/outs can be configured to receive/send spdif via adat ports manually.
The rme adat in adapts to the incoming signal being adat or spdif. It's output can be switched to either manually.

I've got no experiences with spdif over toslink though.

To anyone interested:
 
I figured out how to record a dry input signal while monitoring with wet effects (Dynamic, EQ, and Reverb) using the MOTU gear and CueMix FX.
 
The key to it is using the Return Assign input pair. I was thinking again about why would MOTU say "Input signals to the computer can be recorded wet, dry, or dry with a wet monitor mix, but we're not seeing it happen. I never thought about this much because I use the DAW software (SONAR) to use effects and monitor them. Nevertheless, I read about the Return Assign feature and figured this must be the key to doing this.
 
One way to do this ( recorded input signals wet, dry, or dry with a wet monitor mix) is pointed out below with Analog 1-2 as the (example) input pair for recording and monitoring with a wet signal:
 
Setup Motu software:
 
- In the MOTU Audio Console set Return Assign to Analog 1-2
- In CueMix FX, on the Mixes tab, set Analog 1-2 as the Mix Buss Master
 - Place Dynamics and EQ on the Output of Analog 1-2 
- Place reverb on Analog 1-2 Master Mix Buss or Analog 1-2 Output pair
 
In SONAR
 
- Make sure Return Assign 1-2 and Analog Input 1-2 are enabled as an Input driver in the Unified Preferences view
- Make a track for recording the dry signal and make its input Analog 1-2 and it's output anything except Analog 1-2
- Make another track for monitoring the wet input signal of analog 1-2 and make its input Return Assign 1-2 and it's output anything except Analog 1-2. To hear the wet signal enable Input Echo button on this track. 
 
Now, when you arm the track you want to record the dry signal for, that should do it. I hope somebody finds this helpful or useful.
 
Cya all around.
 
 

Thanks for figuring this out. But if I understand you correctly, the audio still needs to pass through the DAW even if the fx are DSP based, defeating the point.

Correct, sander, the audio has to pass through the daw, so there's latency, as if you were monitoring through sonar...

What's more: there no return assign when using the motu standalone. It's only there if you're using the motu ASIO driver...

So, there is still NO WAY of recording dry and zl monitor wet with the motu, without physical loopbacking losing channels.