There are standing gaming desks available, I know a PC Gamer editor that has used one for 2 years now due to a bad back and being unable to sit. I've considered this as well, for other health reasons than back, but haven't pulled the trigger on the idea yet. I have enough gaming PCs that I should set one up and try it out.
I had a seat setup like Lawndarts, but I found it a little more difficult to be accurate with pedals being leaned back, and also that my elbows and forearm just float in space, where I normally have them at least partially planted on my desk surface, especially when mousing, and even using HOTAS sticks. Some people don't fly like that though, and a chair like LDs is a good option as well then IMO.
I also haven't had any trouble with the rollers on my chairs moving while using rudder pedals, but they are on carpet, which gives a bit of resistance to the wheels and keeps them in place - not sure if on a flat and hard surface if it would be a problem or not.