As wera44 said, control arms can still be sourced as new, wheel studs and tie rods (replacement item on the steering rack) also can still be bought new. You can even still buy new brake calipers and spindles!
But no new wheels.
Thankfully we now have 1 set of cheap cookies available in the heart of the Southeast (Atlanta) region on Craigslist. Unfortunately we have 4 cars being built right now in the Southeast Region, all early offset. My recommendation to all racers after a few seasons of experience is that you need minimum 3 sets of wheels to race conveniently. 1 set for new tires, 1 set for scrubs/practice/old tires, and 1 set for rains. I now need to source 12 sets of cookie cutters for the new cars which will start racing next season. Hopefully each car already comes with them so that gets us down to 9 sets needed. I still dont see the supply readily available without significantly lowering the quality standard and dumpster diving.
As the SE region director, I am now recommending all new and prospective racers source a late offset car solely because the lack of early offset wheels. There are pros/cons to each offset, and to say that late offset is less safe because of the ball joints is a valid viewpoint, but I have also seen several early balljoints break in the last 2 seasons of racing. The spindle (speedo hole) can also be a weak point in the early offset as well as the weld that wraps the sheet steel around the attatchment point to the crossmember. In the end, its really a wash between early and late offset suspensions and a healthy dose of preventive maintenance, inspections can catch most issues before they become a problem.
What I have provided is a very valid, well researched solution for a growing class. This rule change is proposed with the belief that the class is growing nationally, and we need to take steps now to shore up our viability before it becomes a real issue. As was mentioned before, SE30 and SM both use this rule in very tight spec racing with incredible success. Now that SP1 is getting its own championship in PCA with the joining of 944Cup to the official PCA structure, we may see even more 944Spec/SP1 cars nationally in areas where NASA isnt as popular (TX, Northeast). Add all of these cars into the demand cycle for parts/wheels.
If you are against this rule, I question your honest dedication to improving the class for the purpose of keeping it viable and visible in each of the regions around the country. This is not rules creep, we have reached a point where it is time to move in a direction because of valid reasons. Allowing coil overs would be rules creep. As would allowing chips, ported heads, aftermarket cams, deleting balance shafts, aftermarket body panels, wings... all rules creep because it is not needed.
Aftermarket wheels are NOW needed.