Hey Smitty,
My box is in construction phase at the moment. The actual box (without top, controls etc....) is put together and though I haven't weighed it, it is not really going anywhere. I dread to think how heavy it will be when finished!
I used 16mm MDF and the dimensions of the box are 850mm x 300mm with the top panel 900mm x 400mm.
I am adding some rubber feet to the bottom too so the friction coupled with the weight will ensure that the only reason the box would move is if the entire table is shaking!!!
cheers,
gb.