After market delete kits are hard to come by...you can still find them prety frequently for pickup size engines, but nothing mid or heavy duty. The government figured it was easier to go after the suppliers of emissions bypass equipment than all the consumers and have been somewhat successful at it.
We used to make our own block-off plates for our 2004-2007 DT466e's with EGR. Just took some thick sheet metal and a drill press. With that design coolant is still flowing through the EGR cooler which is a point of failure.
Lately we have had a local fabricating shop just close up the cooler (both gas and coolant ports) which is simpler and appears to look more like stock. In a "don't ask don't tell" exchange we give him the cooler, pretend its for some HVAC equipment, and he welds it closed.

Our fleet is commerical so we're subject to random DOT inspections. Around here they're more concerned with passenger safety than EPA bull$hit, but no need to arouse suspicion.
The benefit to our engine though is the ECM and other computers are pretty unaware of what's going on in the EGR, so once we have everything blocked off we don't have to do any tuning or deal with check engine lamps. The EGR valve still opens and closes but has no idea there's no airflow...
As cadillackid said, the maxxforce line changed all that... the ECM controls every aspect of the emissions control so it gets much more complicated to try to delete any of it. On the one maxxforce dt (2008 ) we owned we looked into trying to delete it and wound up just setting aside some money to pay for the inevitable repairs until we could unload it on the next guy.
One gotchya I'll throw out there is any deleted engine can't/won't be serviced by anything bigger than a mom & pop shop. Once you go down that road, you're committing to doing all your service work or relying on side-work mechanics. We keep a stock original EGR cooler on the shelf to toss in a bus on the off chance we need to go to a Navistar dealer for something my mechanic friend can't fix in-house for us...