GuionM pitched this in a thread last week. I believe it was for a FWD application.
*edit- MidLux chassis*

If it is a FWD car V8 would that motor be a Nothrstar based motor, less low end torque than a pushrod=less wheelspin. An outthere idea here is it possible GM would add 2 cylinders to there 3.6 60* V6. This would make packaging a little easier and could be better balanced (ie: 60* V6 vs90*V6.) Or will is this a lower displacement LSX based motor designed for FWD usage? Anyone have any input or thoughts on the subject.

 

I am guessing it is the current 4.8 LS1 based truck motor already in Silverados.

 

I do remember a LS1 Monte and Impala but the reason it couldn't be made had to do with the 4T80E transmission. It was the only FWD tranny capable of handling the torque and the W-bdoy had to be modified to handle the power. Now we know the new trannies are coming out that can handle more power I guess it is just a matter of time before they come out and the Mid Lux gets used for the FWD Impala or Impala replacement. Didn't Lutz say the Impala would recieve a V8 in 05 or 06?

 

And Tahoes! BTW, love that "little" V8.

 

There really is no cast-in-stone law saying pushrods = low speed torque and OHC = high speed torque. It's typically been that way because OHC can usually rev easier so it makes sense to let them make their power up higher. Modern engineering has mostly negated that, with the result that the LS1 actually makes more power at the top end than the Ford modular, while the modular is considered more "torquey".

So to answer your question, it would be far easier to retune the LSx to have even less torque down low as opposed to trying to make a V8 out of the HF V6. Making a V8 out of a V6 is probably tougher than making a V6 out of a V8. Also, a 60º V8 is not an inherently balanced designed; a 90º V8 is far more balanced.