Start searching TT brands! VPI, REGA, Clearaudio, and so on. Some of these have the bearing, others sell platters. You can find some parts this way.
Search google for DIY turntables, motors, motor controlers...
It really depends on how much DIY you want. You can build a motor controller board, or buy a motor and PSU from a manufacturer, like rega for instance. (I'm not sure they sell motors though)