As you mention the real problem is emulating an emulation. Not sure that wine is an emulation tough. (Linux lovers over the net are saying so. :D) Also because of wine the requirements for running a server will be also much more higher.
But because linux is a free os purchasing a linux vps whit higher capacity will be cheaper than a windows alternative whit lower capacity.
If we are able to run a server under linux platform whit mysql then the establishing prise of pub MU servers will also bee much lower.
Season 12 is being worked on to create a MuOnline with MYSQL and Cross-Platform.
See:
https://github.com/Langerz82/MuMySQL