Accademic Question - first introduction of Aftermarket devices that used CAN

Hello , I hope all is well.
I was wondering if you could help me please.
I’ve written many academic papers on the CAN network in vehicles and am trying to find examples of the first aftermarket devices which used the vehicles original CAN bus and sent messages on the original factory installed vehicles CAN bus.

I'm trying to develop a timeline for the introduction of aftermarket vehicle devices which sent messages on the vehicle's factory installed CAN bus.

Would anyone know what were the first products that transmitted messages on the vehicle's own CAN bus?
Or if you know any aftermarket devices from the early 2000's that did this - all suggestions welcomed
I'm particularly interested in any devices in the early 2000's that were aftermarket installed and used the vehicle's own CAN bus i.e. transmitted messages on the vehicle's own can bus.

These days you can get aftermarket radios, ECU's, diagnostic devices, car alarms, etc. that use the vehicles own CAN bus and I'm trying to see when this first started to happen.

Thank you for considering this request.
All the best,
Gabriel

Might be worth asking aftermarket companies such as Kufatec, I remember them selling CAN bus devices in 2003 and they weren't new then.

I'll blur your lines a bit. The original 'factory' tow bars are manufactured by the likes of Westfalia for VAG. They also sell the exact same kit - including the module that connects to CAN - as an aftermarket retrofit. I fitted one to my B8 8K Audi A4. The module hasn't got any Audi markings on it, but is added to the GVL and appears correctly as 69-Trailer.