Grishka3b: Same as 3, but direct submitting is allowed. If the script encounters no character above 127, it proceeds as it does now, otherwise as in Grishka3.

My own favourite is still Grishka1.

BTW, a normal Submit button can also be made to open a new tab, as I found out two minutes ago, so AC's "option" can be considered:

<FORM ACTION="ThreadNewMess-Sub.cfm" METHOD="POST" TARGET="_blank">
...