I sometimes have a similar situation as the OP. Where I live, length of a folder is not a problem, but it sure is in the nearest "big city". I have further complications, though... many times when work takes me downtown it's to government buildings, and that means carrying NOTHING. PERIOD. Not just into the building, but to and from (subway, usually), whatever else I need to do on the trip, I can't carry anything that won't go through the metal detectors and x-ray machines. Not only for visiting government offices, but for some large food courts in government buildings, and the government-run museums, same thing. They're in the process of "exporting" a culture of enforced helplessness out to the population in general, step-by-step.
To make matters worse, the laws are murky (as they are in many places) and while one most often hears that there's a 3" limit, sometimes they cite laws that mention 2.5".
So, if I'm going downtown and I'm definitely NOT going into any government buildings, I generally carry a sub-3" folder, but it really can't be an expensive one, because some official or other (there are like 30+ different police groups, not counting innumerable private guard companies) might take exception to it. The chances of getting arrested for carrying a sub-3" folder are extremely slim, probably vanishingly slim unless there are other charges, but the chances of confiscation are significantly higher.
In the past my go-to sub-3" has been a Doug Ritter mini-Griptilian, or sometimes my Fallkniven U2. Each of those has problems, though. The mini-Grips have blades that measure, the way the cops measure them, just about EXACTLY 3".. if they happen to be in a mood, I think it's going into the confiscation bin. If they're in a really bad mood you could end up being charged.
The U2 is just a little too nice, and it's not a fast-opener, or even a one-hand opener.
These days, I take either a "stripped" Cold Steel mini-AK-47 or a Kershaw Cryo. The mini-AK is the only knife I've ever bought with the intention of taking the blade coating off- it comes off easily and there's a surprisingly nice stone-washed finish underneath. It's also one of the VERY few that doesn't assume that a folding knife with a shorter blade HAS TO have a shorter handle as well, I don't know why that is.
However, the Cryo is assisted-opening, Hinderer-designed, and all-steel, it just feels bombproof. First choice, more often than not.
Good luck in the search. We REALLY need to fight for saner laws.