Paying in Kind
I have a solution: Oblige anyone who creates long-term illiquid securities to get paid for their services in kind, so that a large fraction of their pay has to be in the stuff they traffic in. This would make them think twice or thrice about the honest risks of the product
Come to think of it, this is what happened to Merrill -- they held on to big chunks of the stuff they sold, and suffered the fate of their clients. Maybe that's the way it should work.

