What I was suggesting wasn't really that much (if you were to compare that code with the existing code). But I think a simpler way to do it would be to make the change suggested in post #6, and also change this (line 164):
Code:
$view->showpage($vbulletin->GPC['pagenumber'], $vbulletin->GPC['perpage'], $base, $navbits);
to this
Code:
$view->showpage($vbulletin->GPC['pagenumber'], 5, $base, $navbits);
But in the existing code you can (or you should also be able to) override the default by specifying a value on the url like Lynne mentioned above, so I was suggesting a few more changes to preserve that feature.
(I modified post #7 to make it easier to see the changes).