Been working on my one too. The prototype was on so I started on a new larger one. Working fine as you can see in the vid. I have changed the target for now to a normal target which can move to any position and raise or lower any time and can stay of for however long - 2 secs for each one in the video.
I am making the tray bit with the servo and target in removable so I can just make a new tray with knock down targets or whatever and just swap over when I want. Its fine as it is now but needs the shaft that supports the target refining as part of a pen and some polymorph isnt ideal ! The tray is not 100% level as you will see, this is because I want to add a sort of rail at the bottom and a wheel or bearing on the bottom of the tray (where you can see a lump of white polymorph) as there is quite a bit of friction and this slows the motor down a bit. Because of this. when the target is in the down position, it is still slightly angled up, once the front of the tras is level, the target will obviously be further down. A piece of steel or whatever right accross the front will then hide the target when it is down.
Plenty more ideas in my head whcih I will share once I get it tidied up a bit.

http://www.youtube.com/watch?v=CILImeb_Mgo