Having been involved in the block design and production from the start, I can say that a raised cam version was never advertised, or even designed for production. The concept was discussed and some checking into the feasibility of doing this was done, but there would be such a limited demand, production has not been considered up until this time.
The "recommended" bore limit is 4" just as Neal stated, and he is right on with the comment about stroke also.
What is being considered for a future run would be a change in the block oiling. Since the design is based upon the Stage II block, oil first goes to the lifters and cam, then to the main and rod bearings.
A study is under way to re-design for priority oiling to send oil first to the bearings, and then to the valve train. This way, oil could be better restricted to the heads and any lifter displacement would not affect oil supply to the mains.