i checked all the systems through evemaps.dotlan.net, not many good moons available
R3W-XU VI-1 has chromium(r16) and thulum(r64)
QRU-EJ V-3 has titanium(r8) and neodymium(r64)
All else is either caesium(r32), which we got already, or chromium, vanadium or platinum (r16).
Do the gasses matter?
EDIT:
http://www.thebabushka.com/eve-online/ok, gasses do matter, will look into that in a bit, but seems
chromium is the way to go, as it reacts with both titanium and caesium, which the Z30 moon can provide
it will produce both titanium chrominde and solerium through simple reactions