Metasploit Framework

This would depend on an embedded ruby interpreter and the supporting scripts

You can kinda do this with AutoRunScript. Just "set AutoRunScript migrate" when setting up your multi/handler and it will do what you expect.

To have that sort of functionality embedded in the payload itself requires two things. First, we need a standalone (unstaged) meterpreter. That's not too much trouble and we've thought about doing it anyway. Second, we need an entire scripting language embedded in the payload as well. This is not so easy. One possible option is embedding something like tinyrb (http://code.macournoyer.com/tinyrb/). Of course, being small, tinyrb has serious limitations on what scripts it will run.

Such an endeavor is certainly not impossible, indeed it would be incredibly cool, but it requires a pretty hefty overhaul of meterpreter.