Do you have/plan for Windows Server 2003? Mind following caveats:
- W2K3 SBS operates on different AD model (3.0) as W2K3 SBS R2 (3.1).
- There's only one W2K3 SBS in a domain – and it is at its root!
- Do not even think to add W2K3 SBS as DC to an existing domain!
- Mind the W2K3 doesn't "understand" and operate trusts – it just removes from AD (in case if you succeeded to joint it to domain as a DC) on the next replication.
…and one more thing to do, if you install a W2K3 pure (means - no SPs): apply SP2 before joining domain. Otherwise you may encounter problem receiving "Timeout expired for semaphore…"