I've thought about doing this for same application. BTW, I googled 220V pilot light and the first one I found was $4.29
AC 220V Red LED Power Indicator Pilot Single Light Lamp 22mm - Led Household Light Bulbs - Amazon.com
Other than getting a shock off a lifted ground (as you noted: same danger as a lifted neutral) the difference is that
all the metal enclosures, boxes, frames, cases, etc. (i.e. the things people normally touch) connected to that ground system could also be lifted to 120V (which is a lot different than a lifted neutral (i.e. most people don't go touching the conductor inside the white wire).
Another purpose of a (green) equipment ground conductor is to drain static electricity. If you're running amps down the ground conductor to the earth grounded end, Ohm's Law says that anything connected to other end will have a voltage rise (including all earlier mentioned metal enclosures, boxes, frames etc..) that sensitive people, electronics, and large animals touch. This is not usually a large voltage rise (depending on conductor length, gauge (resistance) , and amperage), but could lead to some unintended consequences. (Wonder if pacemaker's would be susceptible to this? I know cows are more susceptible to mastitis in these cases grounds. - But I doubt you have them in your well house.