I phoned around quite a few builders, both here and in the US and the one I made best/easiest contact with was Justin Burls.
All the others either away on holiday, didn’t return messages, emails, or did not do custom builds, or were too expensive – which is most of the US frame builders.
The Wolfhound (US) looks brilliant but would work out to close on £2K – for a steel frame!
So, Burls has supplied a few ti 29er’s although his main thing now is ti road frames, all made in Russia.
Here is a drawing he has made
Since then I am leaning to the side of steel as I think this might be the the material with the most compliance and alive feel – more soul
I have found a local frame builder looking into a similar full Reynolds 853 design…