Hey Russ-
you're right on the money with all of that, but I'd like to take it a step further. Of course different operators are looking for different results, I asked the question on Wade's post about what exactly his 2186 was tuned for, in respect to what he needed to do exactly. A professional timber faller in most scenarios doesn't exactly need a lot of RPMs, but rather needs the torque for running long bars cutting a mix of tree species. Most guys here still run 32" bars even though the timber average is down to around 16-19". Firewood cutters I would think need the higher RPMs for shorter bars, as I run shorter bars so I don't rock my chain.
So I would say that build packages could be put together. They don't have to be fancy, but a builder could spell out exactly what is involved for the money. For instance, Walker's main thing is to drop the transfers, enlarge the intake and exhaust ports, and install more ports on the muffler. That's a good standard build that pleases a lot of people. There's no carburetor mods involved, no machining the base of the cylinder or the top of the piston, and his price is right.
Madsens just does some the work to the piston usually. I've been into several of their saws and only one had any changes to the exhaust port. There were no changes to the transfers, intake, muffler, carburetor, or air filter on any of their saws. But they don't charge much either.
Build packages would allow a buyer to decide how far they want to go with the saw. Plus, some models respond really well. I'm strictly a novice, but I've had good luck modifying 044s, 046s, and 066s because they're already great saws from the factory. I haven't always had good luck with older saws, like the Pioneer P-62/Poulan P-655 or the Stihl 075, because those designs are highly proprietary for the time they came out and the builder has to have a high degree of two cycle knowledge to know which changes to the port timing are going to be most beneficial.