in "On The Edge- the rise and fall of commodore" it mentions that a Pet 2001 can be seen in one of the early scenes in of Star Trek Wrath of Khan.
I also remember seeing Garth wearing a Video Toaster T-shirt at Wayne Stock in Wayne's World 2. I just did a google and found the reason why.
The engineer who did the first wire-wrap Video Toaster is a Brad Carvey, brother of none other than Dana Carvy AKA Grath Algar. It seems that Garth is based on Dana's brother.