Customarily going for overkill, I bought a NOS (that's new old stock, meaning an unused vintage part) 5" Zenith speaker and popped it in there; then, a plain brown shipping box and voila! A totally finished practice amp that runs off a 9-volt, gets loud enough to annoy my faithful girlfriend, and can still be used to store some stuff.
It seriously sounds bitchin' too; I'm sure I'll post some sounds up at some point.
In other news, www.3than.com is up again, though without much stuff on it at this point. Stay tuned.