I’m 6’4″. I have been racing for 11 years and I have driven quite a few of the chassis brands available. There is not a chassis for “tall people” and there doesn’t need to be. It’s mostly about setting it up for your height. Seat position is critical and once you get this right everything else will fall in place. The only concern you might have is the need for an extended front porch to move the pedals forward if they are too short for you. Most manufacturers support this option. I used to run an extended front porch and now I do not. It’s a very tight fit but I have made some modifications to make it work for me.
That being said I have had the most success in the past couple of years on my DR Kart. It has worked very well for me and responded extremely well to setup changes despite my height. If you are looking for a personal recommendation from a fellow tall racer this is the chassis I would suggest. They are also recent world champions as well!
I would strongly suggest getting a used chassis to start with until you really get your feet wet. You won’t need a new frame if you are just starting out. You might check with Pole Position Karting in Frisco, TX to see if they have any used karts in stock. Feel free to PM me if you have other questions.