It is said that there are some places where class G goes up to 14500 and then class E starts. However, I find they all overplayed with some special use airspace by looking at NorCal and SoCal Sectionals. Can anyone point me to some non-trivial 14500' Class G places? It is best to see some civilian airport within it.
It can be difficult to find these areas on a VFR sectional (there are very few of them anyway), but on an (FAA NACO) IFR en route chart they're shaded brown, so they stand out very clearly from the background. Here are a few grouped together in South Dakota.
At the western end of those areas there's a public airport, Bison Municipal (6V5):
Look in the Big Bend Area of Texas. Large chunk of what your are looking for on the sectional chart in that area.