> Dang it all, Shawn!! That is such a cool idea, now I have no choice but to
> build a sit on top using the methods in that link. Can't you guys leave me
> alone? ;^)

We're all addicts and we want to drag you down to our level! Bwahaha-ha-ha!

> Does anyone know of a mail or online supplier for blocks of foam like
> that? Or would it be available at lumber yards? I know I've never seen
> anything like that.

I've got a local supplier (Western Montana) for chunks of 1-lb. or 2-lb. density up to 16' x 4' x 30". I'm sure any EPS (extruded polystyrene) manufacturer could sell you the same.

If I remember correctly, the 2# is about $4 per cubic foot, the 1# is $2.50 or so per CF.

I can get it in in about a week--shipping it to you might be another matter entirely!

FWIW, I've heard it's very difficult to shape a plug like that and make both sides symmetrical.

shawn