Thanks for all the suggestions. I can't get bonus miles for online booking as all trips need to be booked through the company travel provider. Also, as nearly half my mileage comes from the BOS-CLT route, which no one else serves, my only option is to either stay with US, or switch to UA. If UA matched status I would consider switching.

As an aside, in the past few months I have had very little luck getting the upgrades.