I thought a D compiler producing Java byte code would be interesting...

[Carlos Smith]

Then, i found this: http://nestedvm.ibex.org/

Quite an interesting idea (If GDC supports MIPS)

-- from the site ---
NestedVM provides binary translation for Java Bytecode. This is done by 
having GCC compile to a MIPS binary which is then translated to a Java class 
file. Hence any application written in C, C++, Fortran, or any other 
language supported by GCC can be run in 100% pure Java with no source 
changes.

NestedVM is the work of Brian Alliet and Adam Megacz. It is Open Source, 
released under the Apache 2.0 license.