I don't think 9v will work--the specs on the "Feature Summary" Page says this:
"Just plug in any DC power adapter (10-24 volts, tip positive or negative)."
Actually there is a discrepancy in the manual about this and i wrote MOTU to find out the official word.
http://taperssection.com/index.php?topic=64422.0 Short anwser : 8-18v DC +/- tip. Speaking from experience, I've powered my ultralite for hours upon hours with a walmart 9.6 volt nimh (i think it's 4400mah). This battery works for hours with the traveler as well, although I've done less extensive testing with that (the unit was only powered on, no signals)
Also, I'm not sure the meters will be as cool as might seem at first glance--if I'm understanding this correctly, the only spot on the meter display that will be of use for 2-track recording with a pair of mics, assuming digital out, would be the S/PDIF OUT pair of meters in the lower right corner.
In your scenario you would also have meters for the two analog signals coming in on the XLR's as well as the digital out levels. IMO the display on the ultralite is better than the traveler. The traveler has no output meters. The ultralite has a meter for every input and output (analog and digital). I've had them all alive at once and it's very pretty. Also more segments than the traveler.
I'd be very interested in hearing reviews on the quality of the preamp and A/D compared to our other gear options.
http://taperssection.com/index.php?topic=63624.0Syncing multiple units....
The manual for the ultralite says no problem with up to four units......the traveler manual says two units should be ok, connected with wordclock (ultralite doesn't have wordclock). Three or four units is risky daisy chaining the wordclocks, instead they recommend a distributor box. I would seem then the the ultralite is more stable for daisychaining, but I'm thinking actually it probably isn't. It's just that since there's no way to improve the sync with the ultralite, they just don't even bother telling you about the issues. Since you can improve sync with the traveler they tell you about the issues and how to correct them.
Note's on black lion upgrade...
They warn that syncing via adat, spidif, wordclock, or AES/EBU becomes nearly impossible with the clock upgrade. Depending on how you plan on using your unit you may want to just get the preamp upgrade and bypass the MOTU's clock. You can set the clock to your computer's internal, or any digital device you're connected to.
In the field...
The ultralite is sweet, nuff said.
I'll get back to you about the traveler.