I have been wanting something like this for ages (wide angle converter that's behind the lens)

Gerry Winterbourne wrote:

Note that I said "design" - a patent might prevent realisation of the design but not the design itself.

Incidentally, in another post you talk of the patent dealing with maintenance of back-focus distance to miss the mirror: for the K-01 there's no mirror and optics could go in the space - would that get round the patent?

I can't actually envisage that Pentax would think the market sufficient, but it it did I'd guess they'd design for their own range of FA lenses, which don't reach the speeds you mention here. The FF DS14/2.8 is the worst case. I accept that it probably wouldn't be commercially viable but is it actually impossible?