Pete, you just answered your own question.
People with well worked out 30X44's, 30X47's, etc, etc. aren't just going to throw out their barrels, reamers, dies and all the other tooling they've got just to build a shorter .30. And there are many Hunter class shooters, especially in the NBRSA, who consistently hammer out winning scores the 'old school' way: with 135-150's and 14-15 twist barrels. These guns are as competitive as anything out there, believe me!
As proof of this, I'll offer up
Tom Henckens IBS National Championship win in Hunter Class at the 2008 IBS Score Nats. with a 30X47-ish case spinning 150's down a barrel twisted 1:14.
Matter of fact, Tom is confident enough in his setup that he's built a 13.5 lb. VfS gun for IBS competition using this same combo.
As the popularity of the Score Two Gun grows, it seems to me we need an easier path for people wanting to get into the 6 Power game. And yes, anyone wanting to do that now can simply build a 30BR and call it a Varmint Hunter gun and shoot in that class. But the truth of the matter is that there will always be more competitors in the Hunter class...so why not simplify everything and roll both classes into one? I'd rather place 3rd. against 20 shooters than win against 2 others. And having only one 6 Power class in the IBS would give the 6 Power SOY some serious bragging rights and bring even more legitimacy to this accomplishment.
One more point: For the last two years, 'Terrible' Terry Meyer has won the IBS Iowa State Score Two Gun championship using a combination of 6PPC
chambered guns: a 6PPC Varmint Hunter and a 6PPC VfS gun!
And while the 6's may give up a few X's to the 30's at 100, winning a 100-200 Grand and/or a Two Gun is all about shooting 10's at 200 and letting the X's fall where they may.
Just my thoughts on it.
-Al