March 31: 25BTC (price per BTC - $200) June 30: 20BTC (price per BTC - $250) September 30: 20BTC (price per BTC - $250) December 31: 10BTC (price per BTC - $500) Total: 75BTC
Now at the end of the year you need to calculate your income. You made 75BTC over the year, each of which was purchased at a different price. When you sell them to transfer them into USD, you need to keep track of _which_ bitcoin you are selling. If you sell one on December 31st, was it one from your first paycheck (in which case you made a profit of $300, which counts as income because you didn't hold it for over a year) or from the last one?
Simply buying BTC with USD from a company's bank account and sending it somewhere isn't difficult. To actually provide a service that doesn't leave employees in a tax nightmare they have no way of understanding is really what matters.
http://www.irs.gov/uac/Newsroom/IRS-Virtual-Currency-Guidanc...