There's also the very, very, very thin bottoms that are unfinished with felt glued to it. Even if you have a good seal around the lid, it's possible you'll lose rH right out the bottom.
Additionally, a lot of what looks like solid spanish cedar is in fact just mdf with a spanish cedar veneer.
Its really up to you, and you have three basic options:
1. Non-traditional, primarily functional options like cooler or tupperware
Pro: Hassle free, inexpensive
Con: Aesthetics
2. Inexpensive imported wood humidor
Pro: inexpensive, aesthetics
Con: Hassle to maintain proper rH due to poor seals, thin bottoms, etc
3. Quality wood humidor
Pro: Hassle free, aesthetics
Con: can be very expensive compared to the other options
Personally, function>form so I'll always skip Option 2. Money and preference dictate whether you go to Option 1 or 3.