[Xenon]

ok, let me descibe the quick and dirty way, hope it helps.

in the template forumhome_forumbit_columncell you'll find this:

<img src="$stylevar[imgdir_statusicon]/forum_$forum[statusicon].gif" alt="" border="0" />

replace it with:

<if condition="$forum['forumid'] == x"><img src="path to image for forum x" alt="" border="0" /><else /><img src="$stylevar[imgdir_statusicon]/forum_$forum[statusicon].gif" alt="" border="0" /></if>

that code will replace the statusicon for forum with forumid x.
you can do that recursively for all other forums as well

as said, quick but dirty