Running Java on top of .Net

Miguel demonstrates how to run a simple Java application using the Gtk# libraries and the .Net runtime. Complete apps like Eclipse can be run too, impressive!
You can either pre-compile Java bytecode to .Net IL, or have this done on the fly by a JITter.
You need to export (netexp.exe) the .Net assemblies you want to use from the Java code. I curious how IKVM exports some .Net types like events and delegates, but haven't looked much at it yet. Update: The IKVM weblog just posted an answer to these.
Also, I wonder if debugging works well through the whole stack.

This brings more water to the debate on the future of the open source desktop platform. Java bytecode, .Net IL, wrappers,...?