As a product goes one of the things that companies look at big time is how much profit can we make vs what they have to develop themselves. I have looked at kitting several planes and the one big hangup is landing gear, A few of the planes that you listed have gear that would be costly to develop as the production numbers would be low. When a machinist sets up a mill or lathe they like to run as many parts as possible without having to change the setup. I bet that you will find if you look real hard that other than BVM and Yellow everyone else has someone like Robart or springair make their gear. Knowing that those companies need to work as subcontractor suppliers to the kit company. They are going to look real hard at what they can take out of current stock or design and use or modify to make the gear you would want, it's just good business. We as modelers will need to either pay the price for low production numbers, custom gear or develop it ourselves if we want planes that will require new gear to be developed. I for one have been studying the F-84 for a few months and the nose gear is the big thing. Take a good look at the length of the nose gear strut and the angle that it will travel. There is nothing stock about either the strut or the retract unit that will need to be made for it to work correctly. Bottom line is the current planes for the most part are the Cubs and P-51's of jets, everybody likes them and there are several different sizes and levels of quality available.