still not quite sure about the "spare" servers. They replaced all of the older WoW servers (which were 3 on for each plus 1 more for the Expansion - assuming the Outland instances use the same instance server as the original). If you count the European servers, the US servers, the Asian servers plus upgrades, its most likely there arent any spare servers.
more or less ur right. 1-2 years to beta and another 6 months to 1 year to release. Definitely not having a beta right after announcement.