While I strongly believe Avid will not play with the Io directly, I think you could potentially use it to digitize analog video (BSP? VHS?) to Avid Codec’d QTs that would fast import into Xpress Pro. IF the Io will let you select a codec to use when digitizing, choose Avid DV or Avid 15:1s. The ugly caveat to this is Xpress Pro won’t read the embedded TC info on its own. I’ve seen many posts here and on the Xpress Pro Mac forums over on the Avid site which explain how to use Sebsky Tools (free) to create a bin in FCP, then batch import the QTs into XPro with TC intact.
Of course the Mojo will give you hardware acceleration allowing for more realtime streams, plus the ability to work in D1-sized uncompressed Avid 1:1 resolution for much cleaner titles and chroma keys.