Lewis,
First off, let me say that "Russell" what were you thinking??? LOL... that "man thing"!
Just make sure you aren't standing barefoot on concrete when you stick your hand in there, or you will find out mighty fast how conductive and grounding concrete can be... LOL.
I have a RATZAPPER that holds D cell batteries, and can kill mice, rats, chipmunks, and squirrels at the blink of an eye... and I don't want to test it on the neighborhood kitties....... but I diverge...
Now, Lewis, I would save the 55 barrel for future use, and larger projects. I predict you will definitely need it! (so keep your eyes open for SS to line it with. )
I would place the beer keg in containment... always avoid potential messy breach spills. An ounce of prevention is worth a pound of cure.
Now I think Chuck R. has been operating his electros pretty close to his furnace, and he hasn't gone boom yet... he is braver than I am... I would still want to ensure some sort of venitilation/dispersal. I am still plotting and planning a basement placement. Maybe someday... as space is not just a premium commodity, it is currently non- existant.
Now if I turn the expensive studio piano into firewood....... ::) :-?
I think that a 20 gallon Rubbermaid Roughneck would work well, and they are cheap, and would allow you to put the lid on it when not in use, thereby avoiding the "my kitty drowned while playing with the electro scenario". (Currently $13.97 at Home Depot, but regularly on sale for $9.99).