The different action lengths will take more work. But the bedding arrangement isn’t that hard to deal with. McMillan offered it for years and the laminate stock producers also cater for it.
You can always use a Tikka style recoil lug.
I know a a lot of enquiries have been made on the forum. Could say a model S stock be considered as a trial with non refundable deposits be an option to make it viable?
Currently the only aftermarket option for Sako 85 that aren’t laminate are a single company from NZ. You would have rather a large client base from the northern hemisphere.
I’m sure you would get a minimum number of orders to make it viable. If I had the skills it would be something I would be involved in.