Yeah dude, I hear you...
I was absolutely thrilled to see that my Weldcraft came with a full swim step.
A full width platform out back adds deck space for you and at the very least gives you storage options like coolers or kicker fuel tanks.
I cannot honestly recommend a better custom marine accessory or custom fab shop than Three River Marine because there is nobody better.
However, the modification you're considering looks very straightforward and you should be able to get some local, Tacoma options by googling Tacoma aluminum fabrication.
Good luck and happy swim-stepping!!!