Donald,
Thanks for giving the implementation specifics for using the portal method of launching SAP GUI. This doesn't however address the security issues we discussed with the cookie being sent over the network. I would always recommend that a customer considers security as a priority when implementing any kind of authentication system. Also, in my experience a lot of customers don't want to setup and maintain a Java stack just to login to an ABAP system, and some companies have a no-Java policy. In summary, this is a valid option (no doubt on that) but it is not for everybody, and not the best option.
I'm sure we could spend continue discussing the pros/cons of using a portal if we wanted to, as I can think of many reasons not to do it that haven't been mentioned on this thread. I don't think we need to go into any more details on this thread since we have clearly highlighted the options and we should let Madhu ask any questions if he has any.
Thanks
Tim