You wouldn't believe how difficult it is to source non-white 2mm rod in any material other than carbon fibre! Of course unless you want to purchase by the tonne from China!
I think I'm just going to have to run with white 0.080 (2mm) styrene from Plastruct (bought in bulk and cut to size to supply with the bases). I feel that extruded styrene is going to give the best results for the most economical price - it's strong, rigid and has a lot more flex before it snaps, unlike the moulded clear styrene used in the GW bases and stems. Of course, brass is the ultimate material, but it's prohibitively expensive.
So a black base with white styrene stem. Will everyone be painting it anyway?
There has been a slight hold up on the bases (an issue with the mould had got the bearing marks off-centred) too. I'll keep you posted!