A little while ago McGill performed a survey asking whether the administrative staff would consider switching from Microsoft Office to OpenOffice.org. The results of the survey weren't shared with us, but seeing as there has been no movement on that front, I believe they were unfavourable, and it's hard to blame the responders -- switching from one software to another is always painful, especially when it adds to your other duties.
Nevertheless, I think that the responses would have been more positive if the question had been framed slightly differently. Now, I don't have any numbers on how much MS Office license costs or how many users it covers, but let's assume that we have 1000 people working in various administrative offices and that MS Office licenses cost us $200,000 annually (NB: I can be dramatically off here on both numbers).
I betcha if the question was "Would you consider switching from Microsoft Office to OpenOffice.org for a $200.00 annual bonus?" the answers to that survey would have been different. Add to that license costs for Oracle (PostgreSQL), Windows (Linux), MS Exchange (Zarafa), Sungard (OpenERP), etc, and you're talking real money going straight to your employees.
Just a thought.
Update: I'm not naive and this will, eventually, translate into savings for the entire company -- if your concern is that "execs" will never "go for it" if the savings all go to their employees. The workforce is not static and the payout bonuses will only go to existing staff to provide them with real monetary incentive to switch. Newly hired employees will not be eligible for the "platform migration bonus," so, depending on the company's attrition rate, "execs" will start seeing the savings come back into their budgets in only a few years. Look at it this way: in 10 years you can still be paying $200,000 per year to Microsoft, with extra money thrown into the pile every 3-4 years during major upgrade cycles, or you can switch to a free/libre solution, give employees a real monetary incentive to switch, and see these savings come back into your budget after a few years.