funny you should ask... I got a mailing today from Hofstra about a fellowship for students who want to work as LGBT advocates. it doesn't give an exact dollar amount, but it says something like "substantial" plus funding to work with LGBT related non-profits during the summers.
UChicago has the Stonewall Scholarship, which again isn't listed as a specific amount. But I like to think they don't name and publicize a scholarship if it's $50 a year and a free school sweatshirt.
University of Washington has a new-ish program funded by the Gates Foundation that provides full tuition and a living expenses stipend for students committed to public interest in general. many other schools have public interest scholarships- georgetown and nyu for sure.
On a related note, I went to a workshop about anti-gay statistics at the National Gay and Lesbian Task Force Conference a few weeks ago and was pleasantly surprised to find it was being given by a team from the Williams Institute of UCLA's law school. I had no idea such a thing existed. It's a whole institute devoted to sexuality law at a great school. I was really impressed and after more research, am applying to UCLA. They have a special concentration in Public Interest and Policy that looks really cool, too.