Feedback/DRO DIY

Hi again folks,

Just looking at an interesting page someone made with a tutorial on
building your own ISA DRO card for under "fiddy dowwah". <a
href="http://www.boondog.com/%5Ctutorials%5C7266%
5C7266.htm#Initialization">HERE</a>

It's only 2 axis, but you could just make another one and put it on a
separate IO address to give you 4 axis. Could something like this be
made to work with EMC and a step/dir driver? Or would that require
some major hacking and recompiling?

As I've had and keep seeming to have all kinds of problems with lost
steps, I've become very distrusting of my mill setup, so something
like this seems the way to go. Does anyone know of any prebuilt
DRO/feedback systems that are somewhat low cost? (The cheapest I've
seen a DRO card for was about $200 - definatelt not worth the price).