Great hack Josh! I've just installed it, so my beta testing is in it's infancy, but I think I found some problems with the instructions.
One of the steps is to open and edit showprofile.php, yet this is not listed in the files altered list. The only showprofile.php file you have listed there is /languages/english/showprofile.php.
In your files altered list you have listed /languages/english/online.tmpl. Should this be online.php?
You also have one instance of the word Fidn:
Well, there's the latest rants from beta-testing. The hack itself seems to work well though.
Thanks again!