Word of a big exec shakeup at RIM leaked out just ahead of the company's quarterly earnings late last month -- something that was then quickly confirmed in said earnings report. It looks like that wasn't the end of it though, as RIM has now also confirmed the departures of two more high-level executives. That includes Senior Vice President Alan Brenner, who will be leaving after an unspecified transition period, and Alistair Mitchell, a VP for RIM's BBM service who has already left the company. No word on any further departures to come (willing or otherwise), but given Thorsten Heins' talk of a "comprehensive review" it certainly doesn't seem like the most remote of possibilities.