SkiLab has yellow and orange. Although if memory serves me right, it seems like the yellow wasn't as fluorescent as I was hoping, and I know at some point I got some fluorescent orange from someone that was fairly translucent - not sure if that was from SkiLab or not.
I tried the most neon orange paint I could find under clear bases. Between the epoxy and hazy base material it lost a lot of its brightness. Still bright orange, but not nearly as neon as a colored base would be.
we're using fluorescent Nazdar ink on a clear Crown base, and it definitely loses a lot of it's vividness. sometimes the problem with the true neon pigmented base is that it comes out 'speckled'. this is why we're screening, because Crown wouldn't even make the colour we wanted... said that they have tried the colour we wanted before, and it didn't leave the factory because it didn't pass quality control.