Dan,
..higher V1 helping with close in obstacles?
Actually, I rather like your reasoning .... the reasoning is geometric - for the same weight and V2, lower V1 results in longer TODR, higher V1 in a shorter value. This all presupposes a failure, of course, and is normally limiting.
If a close-in obstacle is the limiting factor for this takeoff, then a higher V1 will improve the calculated obstacle clearance and maximize the RTOW, assuming that some other consideration doesn't become limiting in the process.
The question of overspeed V2 takeoffs needs to be looked at from two viewpoints. If the AFM provides data to account for this procedure on a longer runway, then RTOW credit can be taken for the improved climb gradient availability. However, regardless of that, if the aircraft happens to be a few knots above V2 when the failure has been sorted out, it is preferable to hang onto the higher speed for the same reason.
I don't know if I have any specific data for props but I would expect that the same results apply. I vaguely recall one turboprop with provision for overspeed calculations but the memory is too dim to bring the specifics to mind.