Well Bombardier have only produced 1 GA Aventra, and still haven't produced any SWR or WM Aventras.
Hmm that is concerning though considering that the first GA Aventra was produced in September I'm not convinced that they haven't produced any since.
Actually Siemens have the Desiro Verve, which does have the option of a Bi-mode, which looks very similar to the hydrogen fuel cell system proposed by EMR.
Ah yes I'd forgotten about that. Siemens of course are quite keen on building new depots for fleets that they produce. See York, Ardwick and Northam. They don't always go for new depots of course but they're one of the manufacturers who does.
But where would a new depot be built?
I was unaware that there was no empty land to be found at all in a suitable location on the MML. If it is not the case that the entirety of the Midlands is covered by buildings already then I'm sure a suitable parcel of land in a convenient location near the line could be found.