It's not the biggest OEM marketplace by a longshot (more of a boutique marketplace), but there are a few modules for modular synthesizers that use RPi's inside.

It's not the biggest OEM marketplace by a longshot (more of a boutique marketplace), but there are a few modules for modular synthesizers that use RPi's inside. The two I can think off off the top of my head: Sleepy Circuits Hypno and Erogenous Tones Structure, both video synthesis modules.