Stock block strokers based on the Iron block 6.0L(LQ4/9) seem to be very popular now.

I have found several (sub-4 inch) 3.8,3.825,and 3.9 inch stroker cranks.

Callies makes these but I hear they are available from other sources.

A 383 or 396 CID LS based Stroker looks like it is possible know without being undersquare.