I work for a Canadian investment bank [CIBC] and we discussed this possibility at a round table the other day. First of all, RIM will be bought out only if Mike and Jim decide they don't want to play anymore. Neither one of those guys is capable of taking orders from a parent company. From what the employees at RIM tell us, these guys both prefer to do the bullying, not be one of the bullied.
Second, as far as I can tell RIM is a Canadian company with only wholly owned subsidiaries in the US and other markets. To buy RIM would likely require a foreign company outside of Canada since no Canadian company could afford to buy them. Ownership by a US or European purchaser would trigger a large number of devastating regulatory repercussions which would wreck the RIM business and operations model. Most foreign accountability or obligatory regulations that apply to the subsidiaries do not seem to currently apply to the RIM Canadian parent company so long as it remains a Canadian entity. So, there is no advantage in buying RIM, and even less to gain by selling RIM to a purchaser.
That being said, there are a number of other signs the company could be sold with very little effort. There is no pension plan for employees, and despite recent news, there is no longer a stock plan except for a few employees in senior management. The wages and benefits are very low by any standard, so severance costs would be minimal. The company seems to be seeking out lower cost areas to do business.