Hi Bethany Lee,
Having worked in the Courts for a number of years, I know many court reporters have software which 'translates' their shorthand into normal text. However, it is an imperfect system that doesn't recognize many phrases, names and words. I assume you are talking about editing this type of unfinished product and I think it would be a great niche. That being said, I know many court reporters simply do their own editing as they go, so I am not sure of the size of your target market.
It sounds like it could work out very well, especially if you got a favorable response from some overworked court reporters! Good luck!