we are using comtarsia client and comtarsia proxy for pool PC's to logon into several AD domains without domain joning. comtarsia is a very comprehensive product. you can define multiple logon tiles with customized label and logo for each AD domain and a central proxy service forwards the logon request to the selected domain. additionally a agent can synchronize the user accounts and passwords to local domains ....
comtarsia support is helpful by finding the right configuration.