Would like to have a 6inch barrel replacing the 4 inch barrel on a new python. Any thoughts or ideas? Crazy?

That would be an expensive project.

First, you're not likely to find a 2020 Python barrel, Colt isn't releasing any, and if you want an original Python barrel you'd have to have a New Style barrel thread version.  Those can be identified by having a single pin retaining the front sight.

Second is having a genuine expert pistolsmith with the proper tooling do the job.
Currently, the only person to trust for that is Frank Glenn.............

http://glenncustom.com/

He's an American Handgunner Magazine Top 100 pistolsmith, and his turnaround times, pricing, and quality of workmanship is top of the line.
Note that there's a LOT more to doing a proper barrel changed then just screwing the old barrel off and a different one on.
Even many pro gunsmiths have no idea of how to do a correct revolver barrel job.

Probably, you'd be way ahead to sell your 2020 and buy a new 6 inch version.

Thanks for your insight.
I was kind of thinking the same thing. Was looking for confirmation I guess. Thanks again.

I pestered Colt for a year and three months just to get a gold bead front sight. I wanted the sighting option that was promised, and was willing to pay for it. I think they just sent me one to shut me up.

You can call them about a barrel, but you'd probably get the run around. If you have the gun already. Your options are pretty much to sell it and buy what you want, or have the barrel cut and front sight refit.

Just find an original, better anyways

Success!!!
Found an even trade 6 inch n.i.b. for the 4 inch n.i.b. we both had the original boxes and all contents. I'm happy .
Now I'm gonna give it a gentle hand polish this winter.