I have a Drupal 7 installation with the domain access module installed.
This installation i have connected many domains with different theme, but basically they have the same core and the same database.
The problem is that the domain access module support the single sign on only on subdomain and not on primary domain (domain cookie stuff).
What i need is a code/module that implement the single sign on, so if i login to the [url removed, login to view] im logged in also into domain2.com.
Basically i think that this problem could be solved generating the cookie for the list of the domain installed on Drupal, but i'm not sure.