For my first screen I just called up the Good Guys and they had a manual pull down for about 250$. I mounted it on a hinge on 1 end and used a closet clothes rod to hold it up when I swung it up. It never even fell! http://www.avsforum.com/ubb/tongue.gif
I'm not sure what the gain was I think it had the Sharp name though. I'll pull it out and take a look. I moved and it is stored in my garage still.