No, I'm not....and that depends on your definition of "work".
First, I have no child portals, they are all created as parent portals, 8 in total. This random log out happens to me as a superuser and to one at least one of the admins of on one of the 8 portals. I am sure it will happen to others as they begin to use the admin features more.
I can also reproduce this on my localhost using SQL Server 2000 Windows XP and IIS 5.1
When talking about "working" my experience is that after logging in as host or admin and doing admin functions I will do some action that causes a page to refresh and instead of seeing the page I am supposed to, I get the login page. Once logged in again, I am at the page I started at, but have lost the data I entered before the log out happened (which you will not be notified about until you see the log in screen again) So technically things are working when you logged in, but staying logged in is impossible for me. I get logged out about every five minutes of continuous admin fuctions work (like adding pages, creating portals, uploading skins, the list goes on...)
This does not happen to me if I am using firefox, so that is how I am getting around it.
As for the 4.1 release. I do not think it will be fixed as I am not sure anyone from core is looking at it. If they are and need help I would love to because this is a huge problem, since most users are using IE. Several users in this thread have done a lot of works to pin point the fact that IE is losing the DNN cookie, but no one can figure out why.
One last note. If you are not logged in (you are an unregistered user) things work fine, but that is not exactly the goal for a portal like this.
I hope this help and if anyone finds a solution please post right away.
thanks.