Just to add some more thoughts on the idea of a "do it yourself" monitor instrument :-
Unless you're really wanting to save every penny, and enjoy the rewards of tinkering with the the bits of hardware, it doesn't make a lot of sense to me to go in this direction.
The X-Rite MONACO OPTIX XR is listed at $US250 in their online store. This is a DTP94, and I'm told by someone who has the technical manual, is very similar in command set to the DTP92. If you ask them nicely, X-Rite may well be prepared to sell the DTP94 without the software, so the price could be something like $US150-200, for a high quality instrument that has every prospect of being easy to interface to.
In my book, it's well worth a couple of hundred dollars, to avoid the hours of messing about with stuff that may not end up working very well.
(Since there seems to be some interest in support for a more current display instrument, I'm looking into getting a DTP94. We'll have to see how X-Rite responds.)
Graeme Gill.