Since these spam bots ALL seem to use a smiley face as their post icon... why not make a warning for a human-user to not use the smiley, and if so, automatically delete the post or ban the user.

fair point. been mentioned before, but yeah.

are you allowed to modify invision? is there anyone who can?

Or how about just updating the forums? They are like 5 years old.

If the spam is getting to you (and I delete it 5 to 10 times on a typical day), then Cam is the only person who can change anything.
He personally paid for the forum software, so I don't know if that cost covered unlimited upgrades to all future versions.

Deleting based on smiley face icon would work - heck I'd write a SQL script to do it behind the scenes if I had access to the MySQL database behind the forums. But I don't, I only have access to the moderator interface of IPB, so I fire it up every few hours and whack out the smiley faces.

I don't mind them. Ipa is doing a good job keeping the forum clean (thanks for the work Ipa).