Specular Materials on iPhone or Android?

Is it possible to have material with some amount of visible specularity (reflection, refraction behavior to light, etc) on the iPhone or Android? I've tried all the specular materials I could find, a couple of shader snippets from online, and... no evident specularity.

Sort of. The reason you don't notice any specularity, most likely, is that SeparateSpecular On doesn't do anything. (This is true of iOS devices; I have no experience wit Android.) That means that your specular highlights are being multiplied into your texture, instead of added, which is generally a much more subdued effect. I'm sure this can be overcome with programmable shaders, but pure ShaderLab code will fail you for shiny things. I reported this bug a long time ago, but never heard back. If it's a hardware limitation, fine, but it at least needs to be documented.