There were never any white dashpads offered (nor are there any being produced currently). The problem would be a very harsh/bright reflection up onto the windshield. It would be nearly impossible to see through to drive. There are currently neutral-colored dashpads available, however. They're kind of a buff or egg shell color. That must be the "ugly white" color you're referring to. Yes - they are meant to be dyed - and usually give great results.
If your plan is for some custom, all white interior - I would strongly urge you to reconsider the dashpad (and carpet!).