This proposal essentially ended up as part of v6 in the form of 6to4. 6to4 uses an L4 protocol rather than an IP option, but that's more or less equivalent (and

This proposal essentially ended up as part of v6 in the form of 6to4. 6to4 uses an L4 protocol rather than an IP option, but that's more or less equivalent (and since there are a fair few routers on the internet that drop packets with unknown IP options it ends up working better). But v6 doing something has never stopped people from complaining that v6 sucks for not doing the thing in question...