I'm a big fan of the 3.5" - 4" range personally. I honestly feel that if you were to make a 3" Acies, it would be a big seller. Whenever you release something with a 3.5" blade there is always going to be a group of folks who want the "mini" version.
I agree totally, from a marketing standpoint take a great design and scale it down. Personally I prefer 3.5 to 4 in folders but in the land of sheeple I go 3 in or smaller for legalities sake.
PS since you are A.G. I want you to know your sting boot knife by CRKT is awesome. Keep up the good work.