I know of a Mom & Pop hdwe store that still stocks all kinds of other stuff the chains don't, carbide being one of them, but its an hour's drive. The chains are local.
There is a local welding shop that used to have an acetylene generator. Maybe they still do, though at the time I could buy it from a local hdwe for sixteen cents a pound. Times change, eh? No more local hdwe stores either.
As far as lamp oil goes, even the fumeless lamp types put off fumes that accumulate in a tight house. They can also spill too, but if a carbide lamp gets spilled, only water comes out.
I do know where I can borrow a hat lantern. That might tell me whether it would work inside.
The advantage over a propane lantern, which we use during power outages, would be that its a lot more compact and portable. I'm also thinking bicycle lamp just for the fun of it.
Ran accross this interesting site, but rather than paying shipping from India, I'd probably make one myself.
http://www.jkdey.com/cycle.htm