I'm actually in the game as well... however, I tend to make this a partly commercial product.
It's gonna be a harmonic current analyzer.
I investigated hall and GMR based sensors etc.
Besides their non-linearity, my problem is that I want to get at least up to 9kHz... so ATM, I'm rather sure, I will take the shunt approach.
From my preliminary research, 24bit audio ADCs should be fine... but there are relatively affordable 32bit audio ADCs with 768kHz sampling rate around.
My intention is to have them isolated and floating at mains potential and doing U/I per phase with the 2 channels.
Not the cheapest option, but it should get me there.
However, I just need to measure 50mA on 16A... that's only 1:300