"Clearly, if the Allen Array could be used, then no only would the MERs be able to transmit more data, Mars Odyssey would, and Mars Global Surveyor would as well."

Are you suggesting trying to use it for a DTE mode of UHF operations by the rovers - or simply augmenting the DSN with X-band? If the latter - then given that power constraints limit X-Band DTE HGA sessions with the rovers, you would only be getting more time with Odyssey and MGS - which, as it is, already transmit for as much of their orbit as is necessary/possible. If the former, then given that the LGA on MER transmits at 80-120bps, I'd be interested to see what bit rates one could get using the UHF antenna ( which typically operates at 128 or 256kbps and I believe 8kbps during EDL to MGS ) in a pseudo DTE mode given that it is a lower power transmitter than the X-Band LGA, and if it even has modes to operate at a low enough bit rate to work. I see no reason why it might be better than the LGA in a DTE mode. Attempts were made by Stanford to listen for the EDL UHF signal which MGS succesfully recorded (an 8kbps session )- but found no signal.

Doug