I believe this question mat have been generated by David Vizard's speculation in Popular Hotrodding talking about the 5.7 block. Vizard's words in blue
"A section through Chrysler's cross-bolted-mains Hemi block shows it to be a precision casting. This means that for its 5.7-liter (345ci) displacement, it is lighter than a typical comparable displacement engine. The down side of the weight saving due to casting precision is that big over-bores are out. "
So he's saying a new block is needed for significantly larger engines - that's what the SRT8 got.
Although experience may paint a different picture, this block, for a real performance application, should probably not be bored more than .030 over.
He's guessing - based on his considerable experience - that .030 is the limit for the 5.7 block
"Having said that, the factory appears to have built in room to grow this block to significantly more cubes. Our guess for the future is that 400 inches is practical and the magic 426 inches might just be possible".
He's saying that future new hemi block/crankshaft combinations could yeild 400 to 426 .The SRT8 block will not carry a such a large overbore - and with the transmission it's mated to it does not make sense. The transmission is a capable and advanced unit, but Chrysler wants to stay within the sweet spot of relaibility, with the torque they put through it. I can cite many examples in the past where manufacturers were not as responsible: in fact they were outright negligent. I applaud Chrysler for it's decisions.
The SRT8 is a well put together, balanced package. I for one would not consider messing with it like that. Any future engines by the factory with beefier transmissions, and other upgraded drive train, and other components would be a different matter.