I've now heard whispers from both BT and VM that a deal's pretty much done and an announcement is imminent. I'd imagine the £12 for SD, £15 for HD, is what we'll see, same as Sky.
Pure speculation ahoy: an alternative would be that VM may subsidise it for the first three months and include it in TV XL. I wouldn't have thought the cost to VM would be that high and it may prove a sufficient lure to retain or attract casual footie fans who don't want the full Sky Sports extravaganza. Not sure how that would sit with BT but I would have thought it would be one of the options Virgin may consider.