No experience of any companies as such as my 90 will benefit from the same at some point. I know one of my local independents does chassis changes using Richards chassis amongst other mechanical work. Worth asking your Indy for a quote, although...
We had some Romanians living next door, very dodgy and somewhat annoying. Mind you he explained that his whole country is like that and everything is open to a bribe, even to get a school place.
I have read the 3 litre fits in the place of the 2.7 just use all the 2.7 ancillieries.
D3 3.6 v8 exist, you just need a 2007 onwards donor d3, I think the Russians did the conversions first, then it started in the UK and now a company up...