When I say Least build tools 3d printer. Like not all of us have option of a laser cutter. Lets be truthful they are not a cheap item to have. For me I could not do the cut try cut try since I would have to put my order in to a thrid party cutting firm.
http://reprap.org/wiki/Prusa_i3 Is fairly low part. I would really like to see how far you could get on a 3d printer when you are restricted. Drill press, bought supplies and power and unpowered hand tools only for production and general printer for printing out plans. Even printed parts to a min.
Yes point on the requirement that it must fit in a aprox briefcase size brings a head ache.
3d printer is safer to build at first than most of the others like lazer cutters or mill.