Christiaan,
Since you were discussing the scenario of a nosewheel not lowering and that the CG was over the main wheels may I suggest a rather (amusing at least)
possibility ?!!
With a nose gear jammed up but all other gear lowered normally could the Flight Engineer pump fuel rearward adjusting the CG aft sufficiently to allow the Concorde to settle back on her 'Tailwheel'
I realise there would be some damage, especially in light of what has been said about the occasional tailwheel contacts but I imagine it would be less than lowering the unprotected forward fuselage onto the runway.
Of course some pax might have to move to the back of the cabin too !
If the CG was adjusted this far aft would there be controllability issues ?
There could finally be a use for the 'full down position of the visor' landing in this attitude !