Michelin make tubes in all sizes, at least I have never had a problem finding them here in Norway... They cost next to nothing. Check with your local tire shop..
Rune, what tyre and wheel sizes have you run your tubes with?
I don't have that fancy wheels but they're still tube-type, never had any trouble using tubeless tyres with them, but I have been thinking is there really a safety issue or not with the tyre coming away from the rim when deflated
On the other hand if I am thinking security then 50-something Volkswagen is not safe and never experienced a puncture with Beetle