Recently I watched a presentation[1] by the director of MIT's fusion program, talking about their ARC design. They want to minimize physics risk by using a standard tokamak, but take advantage of new commercially-available superconductors to make a net-positive 200MW reactor that's ten times smaller than ITER.
He mostly talks about practical engineering issues: modular reactor construction, easy maintenance, testing current flow through joints in superconducting tapes, 3D printing a reactor chamber with complex cooling channels, immersion in FLiBe for ample cooling and breeding 14% more tritium than the reactor consumes, etc.
The reactor would be about the size of JET, which was built in four years. MIT has pretty good experience for this, since their Alcator C-Mod has more powerful magnetic fields than any other tokamak in the world.
Of course the startup companies pursuing fusion are also taking an engineering approach. Here's an interesting panel discussion[2] between the MIT guy and people from Tri Alpha, General Fusion, and Lockheed.