Charlie---good question that i am not 100% sure that it can be. Some of the information on various forums based on actual discussions with Dilger would suggest difficulty in doing it. In fact one string suggested that dilger had many of the plates originally produce and the reject rate was tremendous because of warping and trueness. Others have warned about cracking during polishing or grinding of a slightly warped plate. Talking to the machine shop that trued my platter(just recieved it today), he says he can handle it. His work on the platter was exceptional. I mounted it tonite and wow, it looks sharp. I have noticed an improvement in background noise with this table compared to my other ariadne.
Again, back to your original question, i will be able to report back in a few weeks on its success or not. The ones i have are not severely warped so the shop feels that a hard polishing will true up the platter. They have experience with lots of different materials including ceramics so they feel they can handle it. I will also have the shop bore 8 air ports on the platter. I will develop a plate that will install on the bottom to serve as an airplenum that will feed the 8 ports. The holes will be in two concentric circles to cover the entire width of the bearing surface.