I was testing this module out and thought of a couple of minor suggestions.

If the querystring you are looking for is not in the incoming URL, then dont add it to the Iframe URL.  Currently the module will add 'yourvarible=' to the Iframe URL if there is no 'yourvariable' in the incoming url.

It would be nice to have logic that would allow for token replacement and incoming querystring.

If incoming querystring 'userid' is not null

then Iframe url uses incoming querystring value

else the Iframe url uses the userid token replacment

Hope that made sense...

PS.Thanks for getting "hello goodbye" playing in my head =D