Is it possible on the current version of mybb 1.6.x to have a iframe without any plugins in your signature?
Easiest way would be to add a new MyCode that resolves to an iframe.
You can create an iframe MyCode. I think it could be dangerous though, there's some nasty stuff you can do with iframes.
Why do you need to use iframes in signatures anyway?
/ninja'd
I was thinking without an iframe, just because I want to try some stuff.