I'm hoping a High Power Ambi safety will fit.
Me too.
Called Springfield Armory again today. According to the rep I spoke with, they had a meeting this morning about adding an ambi safety option, installed and fitted by them. But, the rep said that is "down the road".
So, at this point for a lefty, the only option is to buy the ambi safety separately from Brownell's or another vendor and install it or have a gunsmith install it for you.