I've done a few over the journey. A MASSIVE amount of work. Good news is that VERY soon, replacement cabinets will be available.
http://aussiepinball.com/index.php?topic=10274.0
This thread covers it in more detail. For the record, I will not be replacing these back panels any longer..
http://aussiepinball.com/index.php?topic=8955.0
+1.
I cannot wait to see the finished product on these. I was lucky enough to secure a WPC-95 cabinet (brand new) from these guys and the quality was outstanding and the finish perfect.
I think for those looking to restore high end machines (inc 80's Bly/Williams etc) its a most worthy alternative.