HydraBus Boards shall be available soon in online shop of Seeed Studio in about 2 weeks (registered users will be contacted first).

HydraBus Hardware:
Schematic in PDF and CADSOFT Eagle 6.x design (CC BY NC) will be available (HydraBus github) at same time as HydraBus will be in shop.
A template of extension in CADSOFT Eagle 6.x (CC BY) will be also released (HydraBus github) to design your own extension.

HydraBus Firmware with VT100 terminal through USB VirtualSerial port:
V0.1 Beta will be available (HydraBus github) in about 2weeks on github, as I'm cleaning stuff (microrl and basic commands), it is already integrated in ChibiOS 3.0