There are some steel panels that GM uses to bring in vehicle kits,the sizes range from 7ft x 3ft,4ft,5ft etc. I have used these panels to build a 20ft by 10ft 2 room site house: you assemble them together (no timber even for roofing) by welding and then the whole assembly is transported and placed on a pre-prepared support/foundation. For doors,you just cut a panel and put hinges,locks etc while for windows you cut and put the normal steel window by welding also.
With this panels,you can put up a 4 bedroom hse etc very fast but probably for this size you need to do the assembling on site and roof using GI sheets. Basically,you can put up a hse that compares to that using pre-fabricated timber panels and finish the interior the way you like.
In my view,this is cheaper than using container,looks neater and you can play around with the design to suit your needs.
In man prudence,in woman patience - Jacob Cats