I'm looking into the possibility of building a CAN bus network with ~400 nodes in it. The total cabling distance is about 200m but it doesn't have to be fast; each node only needs to transmit a single packet once per minute so a data rate of 25kbits/sec should be fine.

The nodes are going to be custom hardware, probably using an MCP2515 chip. Power consumption is going to be an issue so I need them to be asleep as much as possible, is it a good idea to isolate them electrically from the bus cabling while they're not in use? In my head that would mean there only actually need to be a few of them connected to the bus at any given time.

What I really want to ask is whether this is A) possible and B) a really stupid way of doing it?