Dustbak,
I like your set up, it's very practical and lends itself to the restricted space.
Just one question, can you put some weight on the top without the arms that hold the top perspex sloping down?
Also, another slight inconvenience is that if you need to spend time setting up, it will probably mean that your posture won't be so good, as you can't put your legs under the table, though I guess you can always remove the bottom perspex whilst you are setting up, and then slide it in when you are ready to shoot.
I am manic about keeping a good posture, years of neglect have left me with a painful back if I'm not careful.
Edward