I've recently built the mouse adapter (based on PS2M design) and the keyboard adapter (IBMkey2.6) and can confirm that they work extremely well. They're not that difficult to make - but care is needed when soldering the keyboard data, clock and reset wires to the keyboard chip on the mobo.
I can send you the details if you want. I'll be making a combined mouse/keyboard adapter within the next couple of weeks. I'll make the details available if it works (and anyone's interested). Total cost of build should be around £10 (16 euros/dollars).
