Whooo boy - the probabilities of finding a 1640 bolt are slim. There just aren't that many spare parts in circulation, even in Sweden. Maybe our friends in Canada are seeing some things through Tradeex.
Darn, forgot about those import/export laws - Alternative path, buy a 1640 in a caliber you like, build the stripped receiver into a rifle of another caliber you like, but with same rim diameter, and then switch the bolt back and forth between the two. I expect if you persevere in your quest, another bolt will eventually turn up and then you'll already have the rifle ready to go for it.
I will be buying a 1640 in 9,3x62 shortly. Your idea is a good one especially since the headspace would be set to the bolt and therefore not an issue but I prefer whole rifles. If I can't finda proper bolt, I'll make one from a couple of 98 bolts. No big deal but I'd rather spend the time shooting than building parts I can buy. Besides, if I build a bolt, it gives me an excuse to add a 98 style bolt stop. I'm not in a huge hurry, I have way too many projects going and still need to stock two M46's.