So you want plugins to be written in NXT VM? Have you seen specs that CfB posted. ATM it seems VM will only be able to do math (and from what I understood VM was supposed to be used for contracts only).
Something like NXTsmtp done in such VM is just "no no".
VM's output -> AM
That AM -> plugin
verification via indistinguishability obfuscator or simpler method if we can find one
Edit: NXTsmtp is ONLY a PROOF OF CONCEPT, not for actually sending emails outside of test cycle
Now you got me lost, WHY do you think VM output will result in AM? Assuming that would be the case:
WHAT would that NXTsmtp plugin DO with that AM?