Manual Account Sync Between Two Domains

I have a challenge to one way sync accounts between two 2008 AD domains in separate forests. I only need to sync giveName, DisplayName, sn (surname) and sAMAccountName.

I need to do this without spending additional money or installing any user agents (i.e. FIM, Quest, etc).

I have an account domain A and a resource domain B, I need to ensure that any name changes, additions and (to a lesser extent) deletions are reflected in domain B. I'm planning on using CSVDE or LDIFDE to export the account information from domain A and into domain B. I'm looking at using a unique identifier in domain A such as the GUID or SID to import into domain B (possibly in a custom field). I'll then be able to use this field to periodically run a Powershell script to check for changes between accounts.

I'd be interested to hear if anyone has a better way of doing this\has done this already.

Thanks

IT Support/Everything