Hmm i have made a greasemonkey scrip to add classes to posts (see
http://blog.thedt.net/ for my scripts)
but I'm pretty sure opera dosnt support xPaths which I use in that , I guess I could remake it to use document.getElementsByTagName (which is SLOW compared to xPaths)
hiding avatars would be easy with xPaths.....which again opera dosnt support(gar!) I'll see if i can add class names to avatars and sigs for each user using non xPaths for you people.
edit:
done the sig class adder
http://random.thedt.net/messengerplusformsignatu.user.js
for greasemonkey right click and hit install....
for opera install it however you install userJS if it creates any errors please post them i didnt use any xPaths because dodgy opera dosnt support it.
to use:
add custom css for the class
mybb_sig_username
eg
code:
mybb_sig_-dt-{background:pink;}
(btw to hide something in css use display:none; )
spaces in usernames are replaced with _ and so are fullstops.
working on avatar thing now.