I actually just finalized purchasing my season tickets today (XX-5 row 10). They allowed me to utilize the young alumni deal which makes the donation for the Plateau membership (usually $500) only $100 for the first year, 200 for the second, and so on up to 500. I graduated in 2005, but they allowed me to utilize it anyways (you are supposed to only be able to get it if you graduated in the last three years).
Make sure that when you donate, call and tell them that you want to go ahead and purchase your tickets also (they were $720 + 35, for handling fees, for two tickets). I was sent my donation in about a month ago and they told me that someone would call within three weeks about what seats were available. No one called, so I ended up calling the office and the guy that answer told me that I should have already put my money down for the tickets so that i would have been assured of getting them...
Anyways, long story short - they are available, just don't listen to anyone that tells you that you have to wait three weeks to get the tickets after you donate; buy them as soon as possible after you donate.