Cant answer that im afraid.. what i can tell you though is that with the 3D printers that are around, making this sort of thing will be in the hands of most people. These devices are early days yet but it doesnt take a genius to see the potential.

Holy S%#t! That's cool. It's a bit more advanced than I need though, the existing target is just a bit of yellow rectangle plastic, probably 2 to 3mm thick. I just don't know where you'd buy it from. Here's a nos one for sale http://www.ebay.com.au/itm/261155097325?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_500wt_922
$75 plus postage is why I'm now looking to make my own. Nothing wrong with the switch component of mine, just the plastic is cracked.