The reference to an ungrounded system being unsafe probably is based on the fact that our solidly grounded systems are that way as a safety precaution: Limiting max voltage to ground; and prompt fault clearing. However, Jon's comment is well worth considering. Intentionally ungrounded electrical systems are still capacitivly coupled to ground, and I'm here to tell you that inadvertantly touching a live part even in an ungrounded system will still deliver a nasty shock.
I still think a high resistance ground might be worth looking into. Otherwise, there just isn't any way that I'm aware of to stabolize & limit the phase to ground voltages.
Lastly, imho, the most outstanding safety issue is clearing any ground faults that may develope. You need ground detection circuits and procedures. & vigilance.
Good luck,
Radar
