OK, then given Domain\UserID you can translate that to LDAP nomenclature and then using LDAP, query it from AD. I presume there are trusts between domains.

I slightly modified Howard's TranslateName()UDF to use an optional parm being UserID and with that I can pull the details I want from AD. I don't use profiles so cannot provide tested code but here is an untested example of pulling profilepath.
Code:

BREAK ON
$users = GetObject("LDAP://ou=Users,ou=bla,ou=bla,dc=yada,dc=local") 
$Users.filter = Split('user')

for each $user in $users
  if $user.profilepath <> ""
        ? "Current path for " +$user.name " is: " +$user.profilepath 
  endif 
next