What crank did you find? Unless it is a 3.5l diesel for the stroke there is no advantage. They all shared cranks. There are a few different strokes. The 3.0l, 3.2l, and 2.8l. But they are all the same strength.
As far as other pistons and rods that fit that thread was the only one anyone around here has tried anything like that. And if your goal is to drop compression by a shorter rod then you will run into issues hitting the crank. etc. etc. Just get custom lower compression pistons.
And as ar as spinning to those rpms you have a lot of work ahead of you. The platform is capable of it but you are not going to do it on a budget. I know a guy that does bonneville with one and he has over 250k tied up in a n/a m104 to run those rpms for just a couple of minutes at a time.
THe head will choke big time well before that and it requires major machining and custom part up the wazoo to make it breath at those rpms and oiling becomes a huge issue. Shorter stroke, etc. etc. etc. Pretty much you name it and you can not spin it that fast stock.