The transceiver and physical bus are independent of the protocol controller and the library wouldn't even notice the difference.
I thought and hoped so already. so that's good to hear..
From a quick look, it appears that all low-speed transceivers are larger than a SOIC8 package due to the extra pins required for the termination resistors among other features, so a board would need to be made for this. Looking at how each device is terminated, it seems to me that a good confirmation of your thought about the bus being low-speed fault-tolerant would be to disconnect the battery and measure the resistance between the CAN High and CAN Low of that bus to see if it reads around 60 ohms or not. From what I'm seeing, I would expect a higher resistance or an open to be read when they are unpowered, but I could be wrong as I've not messed with this physical specification yet. Its also worthy to note that a low-speed fault-tolerant bus is designed for a specific number of nodes in mind since each device has a termination resistance. Hopefully the vendor thought about future proofing and the total line resistance is greater than 100 ohms allowing for an additional device or so.
Now I'm suddenly skeptical about my Jeep's 125k bus even though the high speed transceivers in the CAN adapter I was using was reading the data fine.
I want to make my own board indeed, soldering a PCB is not a real problem. I have looked in to some circuit diagrams and it seems pretty easy to do.
The termination is good point though, I also read about this. I think the manufacturer thought about at least one more device, as there is a connection to a CD changer available on the radio with CANL and CANH. Also, there is an option for a handsfree set, which I don't have. I'm thinking of using the CD changer connection (this way I'll also have a neat solution for connecting my device).
Determining the value of the termination resistors is one thing I'll have to solve indeed. But I'm not sure how to do this exactly. I have included a (crude, sorry for that) diagram of the ECU's, as found in the official technical documentation of the car. So it seems I have six nodes on this bus, but I am not sure how to find the value for the termination resistors for my project. I'm not sure how to measure the termination resistance of each node, as measuring over CANH and CANL is not correct in this case I think. CANH and CANL don't seem to be connected by the termination resistance.
Update for future searchers:
I managed to receive messages on the comfort/fault tolerant/low speed CAN bus of my Peugeot 207, via the RD4 radio. I finally got it working with the circuit as described in
this paper. Comparable designs and more information can also be found on a few German and Russian forums. Google Translate is my friend
I still have to develop a refined 'production' board, as I now only have a breadboard prototype. Also, I haven't tested sending messages yet.