Direct Login Suggestions

Hi again,
            First I wanted to apologize for asking soooo many questions
and thank everyone for giving me so much help. 
 
            Now onto my next question. The application we are developing
is to have no login page, rather a URL with a generated code would be
emailed to the users and they would use this link to login. I have some
basic hunches on how to accomplish this, but I was wondering if I could
get some feedback. I figure I will have to create my own service to
handle this.. but then the trick is that the application that sends the
emailed links to the users would not be written using tapestry.. just
standard javamail.. so I question how I could generate the gesture to
this service.
 
Part of the reason for this is that the email sent out to each user
could be written in such a way that their mail viewer would pull the
page directly from tapestry, and the link would be displayed only for
those users without HTML support in their MUA. Ie. Something similar to
the way that ebay, etc send periodic report emails.
 
Has anyone tackled something similar? I realize that if I wanted to pull
off a ridiculous hack I could just forge the url and have an actionLink
on the page that I wish them to enter from that logs them in.. but I am
not sure if I could sleep at night if I did that...
 
Luke Galea 
Software Development
BlueCat <http://www.bluecatnetworks.com/>  Networks
905-762-5225