Thanks a lot for everyone's interest, and suggestions. Working with Jason and Max is always an enjoyable process for me, and I've learned a lot about optical engineering!
With regards to the suggestion of a solid state shutter, I've already spent some time building an LCD-based shutter system, which I've integrated into both a front-mounted unit for larger formats, and inside an Instax Wide camera. Whilst they both function as planned, their limitations (2 stop light blocking when 'open', and a cool blue cast) have led me to develop my own dual-curtain focal plane shutter system instead. I've been working on that for the last 18 months with another engineer, and am close to a fully working design, which offers electronically-controlled shutter speeds up to 1/1000th, and is battery-powered for portability.
As the same time, I've also been testing an off-the-shelf miniature electromagnetic shutter, which I'm going to be integrating into a new 35mm camera system, along with our new 24mm f11 lens, allowing me to offer a complete camera system.