Oh, didn't read the whole thread. I still haven't completely cause I'm so tired, but here's a alternative to if($show['member']) & else.
HTML Code:
<if condition="$bbuserinfo[username] != 'Unregistered'">
You are logged in.
<else />
You are <b>not</b> logged in.
</if>
or...
HTML Code:
<if condition="$show['guest']">
You are not logged in.
<else />
You are logged in.
</if>