I'm thinking a pair of fire tiles for the top, medium duties for the hearth and sides. Get a long lintel brick (refractory supply place for fire tile and lintel) for over the door. Use some M board or kaowool for insulation (watch out for inhalation hazard). (my refractory guys/candy store: http://www.cutteratlantic.com/products.html
- but find some local to you, shipping will kill ya on this stuff)
It will weigh... as much as the bricks- but it should set up/break down really fast, and would be easy to reconfigure until you have a design that works well.
In all honesty- I am guessing that you could set one up in under an hour the first time.