Class 805, 9 Car IET but with the following changes. The kitchen in the First Class area removed, and GWR HST style First Class seats installed, a kitchen/buffet shop in between First & Standard. The Standard Class end being halved to make way for a Guard's van area, to store bicycles, heavy luggage, Train Managers office. The area which was once bicycle storage made into additional luggage space or fold down seating for busy periods.
*Yeah I know, it won't happen* Ideally I'd like to see a HST2, a bit like the new routemaster, but for a HST.