Louie, I'm inclined to agree with your assessment, the ACTRU needed to be very, very sure White was committed to Canberra for this to be a tolerable mix of risk and reward for them and not a damaging, sponsor and general income killing debacle if White was effectively using the Brumbies as a near term stepping stone.
It was always known that international Test coaching roles could well come open post RWC, including possibly Australia's as many thought if Deans did badly (despite the extension), Johnson's hold on the role was considered fragile in 2011, as was PdeV's, and Mallett was bound to be leaving, post RWCs are the most volatile Test coaches' periods and this was sure to be true in late 2011 and early 2012 just as White was starting in Canberra. (Btw, imagine the outrage if Deans had started to wander elsewhere in say 2009.)
See the latest on RugbyHeaven. Leaks that Brumbies sources have confirmed White has actually already accepted the England job. Sadly, they certainly didn't deserve it, but this uncertainty is turning into a nasty little mess for them that could get much worse. Great pity if it pans out negatively as I thought White would be great for Aus rugby, and the Brumbies, and the ACTRU in principle was to be congratulated for hiring him, not a second-rater.