RE/MAX Main Line
The reason you are having difficulty locating a property like what you describe is because they are few and far between.......I agree with Edmond's answer, you would be better off doing a tear down or reconstructing.
A building lot is so expensive in those great convenient areas that you describe therefor, builders are not able to build anything but big houses to make their profit because of the expense of the lot, and, a one story house is much more expensive to build, more cement for foundation, more roof area to cover etc.
When you want to begin a search, contact an Agent who will work for you and knows the areas you want to live in and has contacts with contractors and/or builders.
There is a house that just sold that sounds like you may have liked it....it was right on Paoli Pike east of West Chester, 15 minutes to the blue route. Sold for $450,000.
If you like, I could send it to you and see if it is "along the lines" of what you mean.
Most that style will be in 55plus communities far out, OR, a custom design that is a "fluke".
I will be listing a 29 year old contemporary on a 2.3 acre wooded lot after the new year, near Phoenixville, the other side of where you want to be. In fact, It is still pictured on Trulia.
Best Wishes, Happy New Year!
By the way, I agree with your comment about the McMansions. Not much character, but it certainly appeals to the mainstream. Good hunting!