You can try Password Reminder, which will remember and auto fill-in your password for any number of accounts so you don't have to type them in but you still have to go to File->Sign in. See
Password Reminder
Also If you know how to use resourse hacker here is how to add a sign out button:
Open msnmsgr.exe with reshacker
Find (Ctrl+F): <element id=atom(suppress) padding=rect(3,0,0,0) content=rcstr(4229)
Result: UIFILE > 923 > 1033
Below this line is </cmdbutton>
Below that line paste the following:
code:
<cmdbutton cmdid=40210 class="ToolbarBtn" layout=flowlayout(0,2,0,2)> <png flip=false idres=1013 class="ToolbarIcon" /> <element foreground=rgb(0,0,0) padding=rect(0,0,2,0) content="Sign Out" contentalign=bottomleft | endellipsis/> </cmdbutton>
Then compile script and save.