Another option would be to request a split of trading fees with the exchange (many traditional ETFs are partially funded this way). That combined with arbitrage opportunities could cover operating costs. Given the current nature of asset exchanges this may be the easiest option. If any exchanges are interested in a revenue split drop me a PM.
That would be a pretty interesting (and simple) feature to introduce. An asset (at creation time) could specify the transaction fee premium. Then I'd have to make sure that we clearly display it on the trading page so there is no confusion, but it would definitely make for an interesting way to support some of these assets.
OOC, what rate would you require? and would you be willing to be a "beta" asset in this regard?
Cheers.