Gun Safes : Fire Safe Manufacturer : Sturdy Gun Safe
if you watch for businesses that are going out of biz you might just score a nice tl15 rated safe if you're patient.
Also watch craigslist. Good news is the used market for safes that size the price is a ton cheaper than anything over 40" tall.
Don't forget about wedding photos, kid photos, tapes and dvds, home papers, wills, & insurance docs. Everything starts sucking up room!