I've just gone through the same search and found that availability of switch type is the limiting factor. I wanted Browns but they are hard to find in stock. Went for the CM Storm Quickfire TKL with Browns for £70-ish in the end because it was the only one that ticked both Browns and £70ish. Its my first mech KB since an IBM KB in the early 90s and I'm not convinced that mech is OMG SO MUCH BETTERZ than a decent rubber dome KB, but I'm in the minority on that.
Anyway, if you are after Reds there are a few more options available in terms of manufacturer and size. Good luck with your search!