Is there a way of configuring a PV750 so that it can only be used with a particular XM500? This is to prevent customers swapping them and losing potentially valuable logging information.

In theory. I am using the internal chip serial number of the PV750 and an algorithym to unlock certain features on displays, as they are pay options for my customers.

I would guess that the XM500 has this capability also, with custom programming. You could have the XM500 broadcast a proprietary PGN/SPN containing its serial number. The PV750 just has to check this against a number that you statically program into it to see if it is the correct XM500.

This is, of course assuming that the XM500 is using serial numbered chips.

There are many ways to lock a PV750 to an XM500. Do you know how hard is someone going to try to use an "unauthorized" XM500?

The simplest way is to use an uncommon source address for the XM500 and/or proprietary PGNs. That would prevent the simplest attempts of using a different XM500 (or other CAN device).

Making the XM500 send an authentication message is also an option but if the message is always the same it could potentially be cloned.

The data could be encrypted in the XM500 and decrypted in the PV750.

How complex does the system need to be?