Got to thinking... if all you want is something to use intermitently, why not an electric griddle? Plug it in, heats in a couple minutes, use it, wipe it off, and store til next time. Quick, easy, and no semi-permanent use of space on your porch.
We have one with as much cooking surface as the on you first linked. Is up to temp in only minutes and cleans easily. You could replace it several times over for what even a modest gas grill costs. If you don't have a convenient plug on your porch, a 20 ft 12ga extension cord is an easy fix.
Brad