Primary in a corny keg?

I've been wanting to expanded my capacity lately and have been looking at different fermentation vessels. I started thinking that fermenting in a corny keg might be the best way to go.

However, I am currently bottling my beers and will be moving in a few months so I don't want to start messing with kegging and building a kegerator, etc.

I was wondering if anybody here uses an unpressurized corny for fermentation. They can be picked up for about the same price as a 6 gallon glass carboy. The biggest drawback seems to be the 5 gallon capacity. I brew 5 gallon extract batches so I'm assuming that a corny will be a little too small to primary in. Can I just run a blow off tube and be done with it? Is this advisable? I've seen other threads about fermenting under pressure and whatnot but that is out of scope for me right now.

The way I see it, this could be a good way to start building up an inventory of kegs well before I actually start kegging my brews.

 

Check it. http://www.homebrewtalk.com/f39/corny-keg-single-stage-fermenter-127563/#post1427432

 

I use a 10 gallon cornelius for most fermentations. It works great!