Canning in the house sucks. It involves putting a pot of water on to boil for hours at a time (some canned goods must be boiled for 30 minutes or more, and if you're doing it, you probably want to do enough to make it worth your time, so that means several rounds), tying up the whole kitchen, and release about a bazillion joules of heat-energy into your home. By the way, did I mention that this can only be done during the hottest months of the year? Yeah.
Beth and I are moving into a rental house in a couple of weeks, and I'd like to make an outdoor canning kitchen (I bet you though ALL my projects were electronics...). What I have in mind is a couple of those turkey deep fryer things, connected together through some kind of Y-valve, with a nice frame of some sort to add stability. A bench, too, probably. I can't build this stuff in because this is a rental, so it'll be an interesting challenge to see how I can do it.