Thanks for the info. I already got a ton of information about canister stoves from http://zenstoves.net/canister.htm . In fact this is where I first heard mention of it being possible to do such a thing...unfortunately no links to specific products.

My canister stove is an Optimus Crux so there will be no inverting of the canister in my case.

Also, this isn't specifically for backpacking...that would be a stretch but isn't completely out of the question. Just trying to make maximum use of what I have on hand or what might be available. For example I always carry the stove (it's tiny and light) but not always the fuel. But I might be in a situation where small propane cylinders are readily available (camping, bugging in, etc).

Unfortunately a big liquid fuel stove with LP gas capability is out of my price range.