Define a standard form factor for a box that can have attachments to it. (Say approximatly 1 x RPi or 1.5 x RPi), that has a secure modular connector that is fed HDMI IN/OUT, Power, a data bus (Ethernet?), and space so custom connectors can be on the other side. Offer panels with a 'startup' block, and maybe 1 or two others for other devices. Ensure there is enough ventilation for passive/silent cooling.

Set up partners to make custom boxes. Things like SSD's in the same form factor storing media to be shared with other media block devices, (HDMI would be unpopulated), a Roku in the secondary/primary position. DTv Tuners with a Coaxial F-Connector for the antenna, etc.

This "Standard media block" connector could even be retrofit to legacy panels by means of an external box, and one master upstream connector.

Does anything like this exist yet? If not, what would be preventing it?