I would be in for that.
ARC does one similar to this....not really a secret Santa perse, but people "donate" kits to the over all list, and people's names are pulled out at random (not necessarily a person that donated a kit, so some might see it as unfair that way as not everyone gets a kit back sometime), and they get to choose what kit they want.
Think I missed out on it last year, but if we have a Secret Santa, much better as you don't know what you are getting until it arrives.
Idea is to take something from your stash you will never build, but if you don't have anything you can bear to part with (yeah right), then there are lots of kits out there for not much money....lots of the new and re-released Airfix 1/72 kits are going for under $12