Such a payment scheme has always existed. The provider with the most
agressive filtering policy has always announced many prefixes which they
wouldn't accept if the networks were customers of a different provider.
Just make your checks out to all the providers you want to reach, and
they'll each be happy to install a seperate circuit for your network.
It worked for tymnet, telenet and compuserve.
In today's Internet a difficult problem is figuring out if they are announcing
a /32 accidently, for a dumb reason or for a good reason. Because my upstream
provider is too dumb to aggregate isn't a good reason.