Here's my progress so far. The crew module is original, the rest of it is scratch built (all the skin panels, the "airframe" structure underneath it all...).
The frame structure that I've built it around I have fabricated from galvanised steel which I've painted in a colour that emulates zinc chromate and also provides some protection from corrosion. The exterior panels are cut from 2mm aluminium sheet that I have cut using measurements taken off a HobbyMaster 1/72 F-111C that I have scaled up to full size and cross checked for the little details such as access panels from high res. "walkaround" modelling detail photo's.
The radome I am going to cut from polystyrene block which I'll shape until its right, then I'll either use that to create a mould for a fiberglass duplicate or I may go with a spray on protective hard finish directly onto the foam plug.
Centre fuselage section will need to bolt directly onto the rear of this section, so I'll have tom start drawing up the plans for a frame to base this on before I get cracking on fabricating that up...