I was looking into this feature request yesterday, good news is lekhonee-gnome already supports this. Lets say your wordpress username is foobar.
So, in the accounts in Preferences window you add the first account with your username and password and Wordpress as service.
Then add another account with same username and password but service as other and type the full url of your 2nd blog following /xmlrpc.php (example: http://secondblog.wordpress.org/xmlrpc.php).
Now you can access both the blogs from lekhonee-gnome