Hello!
Might I offer the solution that worked for me:
My problem was I wanted a single cord to go from my trailer (50amp) smart plug to my generator 30amp twist lock.
I purchased an appropriate length of 30amp cord with a twist lock on one side. I didn't care about the other side as I cut it off.
I then replaced the cut off plug with a 50amp smart plug using their cord seal kit.
Now, I have no adapter (dog bone/pigtail) when I use the generator.
Do note, that you'll have to cut a length of one of the wires on the 30amp cord and bridge the two hots on the adapter.
50amp plug:
https://smartplug.com/product/smartplug-connector/
Cord seal kit:
https://www.hodgesmarine.com/smapkf3...a50a-conn.html
Best!