CAN bus physical layer configuration for more than two devices

1. Many small and cheap microcontroller have CAN built in. Look at some of the PIC 18 with "8" in their part number. You only need to add the physical CAN transceiver, like a MCP2551.
2. If you just want a differential signal, then you can use a number of differential line drivers/receivers. There is nothing wrong with using CAN transceivers for this, RS-485 or others are options too.

Overall, I'd use CAN all the way. You will need a line drivers/receivers one way or another. CAN transceivers are as good as any, but then it's easier to use the rest of CAN. The main difference with CAN is that the lower levels of the protocol have been well thought out and are available at low cost integrated directly in many microcontrollers. RS-485 throws you a electrical spec, then you're on your own.

It's a lot more difficult to get all the details of a multi-drop bus right and robust than most people realize. Use CAN. It's all been worked out and done for you. You send whole packets at the firmware level. The hardware takes care of collision detection, retry, and CRC checksum generation and validation. These are all things you want, and with CAN you get them practially for free.

"Don't use stubs just loop in and loop out of each module" as Andy Aka said. UTP rigid cable may not be the best solution. Use a shielded twisted pair cable with characteristics impedance 120 ohm. At each device/stub wrap the wires or crimp them, don't solder them. The type of splitters you have mentioned are in my opinion too expensive and they just don't add any benefit to your system, except if you are doing hi-tech military stuff. I have installed many CAN devices in industrial environment, kind of monitoring system. As a base rule, I used a good shielded cable, correct impedance (UNITRONICS BUS CAN) and no stubs. I'd suggest you not to use UTP, as the rigid wire can break when twisting it, also UTP has no shield.

EDIT:

@Conway @Lundin:I agree. I have misunderstood the question about vehicle CAN aka J1939. However, I would like to underline that it would be good if you crimp wires and use some standard vehicle connector where you will join also power wires. As for characteristics impedance it matters the conductor diameter and overall diameter (as well the \$\varepsilon_r\$ of insulating material). I have found some online calculator: https://www.allaboutcircuits.com/tools/twisted-pair-impedance-calculator/

The \$\varepsilon_r\$ of the insulator has a standard value regarding the material. If you need perfect impedance match, you have just to choose a suitable wire and wrap them to make a twisted pair. Alternatively you can also inspect CAN wires from a car at junkyard.

Example: http://www.wiringproducts.com/100ft-spool-red-20-gauge-automotive-primary-wire.html

AWG20 = 0.032 in

distance between conductors == overall diameter = 0.085 in

dielectric constant PVC = 3