Thanks to everybody for the nice comments.
Myles,
The furnace, with all of the top detail, is about 47" tall. The bench height is about the same. I'm not sure what the footprint is. The cast house and furnace housing have been very compressed. The furnace is scale.
Cost has been minimal. The I beams, stairs,ladders and trusses are Plastruct. Most everything else is just stuff I had laying around. Wood. paper, tile. TIG rod, PVC, spray foam, fibreglass etc.
Dave