Well, you don't have to be young to ride a fixed gear. All a fixed gear means is that there is a single gear and you can't coast. Nothing about age in the owner's manual.

I will keep my eyes open for you.

I do know that there is a Surly Steamroller in a 54 or 56cm (I forget which size) at The Hub Cyclery, in Cotati. I think it's going for $666, and you get a year's free tune-ups and 10% off accessories when you buy a bike there.