CAN transciever chips are available from Phillips.  This is a pretty cool
network.

LONworks Neuron chips are available from Toshiba and Motorola.  Echelon recently
announced opening the protocol for anyone to implement.  Someone should do a PIC
based transceiver.  Echelon has a web site www.echelon.com

Fieldbus is, IMHO, a mess.

Are you familiar with Seriplex?  It is real simple and cheap.  Check it out at
www.seriplex.org

- Mark Sullivan -