As for WMP 10 - Both my SMT 5600 and my i-Mate SP3i shipped with 10. I'd be surprised to see a brand new unit ship without.
Over here Orange are taking a life time to release a new rom with WMP10....
I'm sure they are not going to release the update for the SPV C500 and force everyone who wants WMP10 to upgrade to the C550, when it's released.
Roll on for Windows Mobile 2005, when we can update our phones without having to wait for the provider to get there act togther.