This emulator is pretty awesome, once you can get it running. Note that it does claim GDB support, which likely means you can get a pure eclipse CDT C project & CDT-GDB-HW-Debugging session up and running against it (making sure to compile with the msp430's tool chain, of course).
http://opencores.org/project,openmsp430
As far as a simulator, the answer is truly 'no'. I would like to be wrong on that... But consider for a moment the number of variants of the msp430, the peripherals, and so on. Not sure if any company can justify that kind of cost!
Especially when launchpad/etc are so cheap and fast.