I'm doing the wheel myself following various online DIY tutorials and will post up a DIY probably end of December. I've practiced baseball stitching, found a local seamstress to do the initial pattern, and I'm currently finding a cheaper source for NAPA leather.
For the heating element you can take apart one of those 12v heated steering wheel covers and incorporate it under the leather and put the switch under where the right paddle should go behind the wheel (my plan at least).
Example of a heated steering wheel cover. Any custom wheel company can incorporate this under the leather.
I'm actually also working on a diy air conditioned seat... but not going to hijack this thread with my diy