Andrew, as a fairly recent returnee to EM, I posed the same question – John in the EMGS Stores recently listed some Kean-Maygib metal wheels, but they were sadly out of stock. In the stores there are some metal wheels from DCC Concepts, which might fit the bill. I too would be grateful to hear of different sources.
Alternatively, could you re-gauge the 00 wheels by pulling them out, or by substituting a new axle for the original?
I am positive there is a solution out there.