The idea of having a future ISSCA National in Indy is a good one and should be pursued. I was just there--for the Brickyard 400--and on the way in from the west we stopped by to check out Putnam Park--an awesome place to hold the road racing competition! There's IRP, too, for drags, and even though there is a "road course" there, Putnam is WAY better. Where is autocross held in Indy, by the way? I'll assume there are some good places to have a nice car show, too.
The one thing we'll have to work around now in Indy will be the shift to June for the Grand Prix race and fitting "our" event somewhere in between all of the other things happening from May to August--maybe we do it in early August, right after the Brickyard 400. There are at least a few of us who would stick around for the ISSCA National that week. For the drag racers, I realize you'd rather be in Indy for Labor Day weekend, but that's probably too late in the summer for the National.
There are lots of options, whenever it happens!
By the way, judging sheets should be in the mail.