I think I have to use 2 pcb's because there is also a PC keyboard interface and IDE interface integrated.
Found a real nice casing. More info coming...

Pcb's:



Schematic (90% finished):

All components available; ordered hard to get components

The MB04 – the ultimate disc interface for the ZX Spectrum

The MB04 will include the following features:

- High Density diskdrive support (up to 1.8 MB)
- IDE interface
- PC Keyboard interface
- Internal bootrom
- Z80 DMA controller
- Real Time Clock chip
- 512 KB internal Flash ram
- BSDos operating system
- Optional Compact Flash adapter
- The MB04 will be cased in a black plastic quality box.

5V + 12V power supply needed.