The two companies I am thinking of using are Zone Creations and EightByFour, both in London. I use them for producing architectural models in my work. They can laser cut perspex direct from CAD file (brilliantly accurate) and CNC mill the MDF also from CAD, also spot-on accuracy. If I go with the analogue stick ideas (see separate post) I could get them to mill out 8mm of the 18mm thickness of the MDF and mount the joystick plate on the underside of the CP, so I don't have that huge ugly plate on the surface. I.e. they can make the CP thinner in a specified area.
As for the edge conditions, yes you're right to express concern... Well I was hoping someone here could shed some light on that

!!! I've heard talk that the buttons can clamp the perspex top well enough, but on the other hand at some points along the edges it could prove to be a problem. Any help here is appreciated.!!!
When I spoke to Happ UK they said thay have a 7 quid delivery charge... How much is minimum order?