Problems with high-side current sensing with 12V comparator and logic
If you have a few hundred mV of signal and don't care about an extra mA or so on each output (or 100uA if you use more expensive parts) you could use TL431 parts to level shift the signal into the common mode range. If the accuracy of the TL431 is 1% that's a maximum error of 24.95V mV, so if your current limit is 250mV your maximum error due to the LM431 is +/-10%. Not great but maybe good enough. 

Or create a 12V-5V rail with a 7905 regulator or a shunt reference. Then  use a RR input comparator such as a MCP6564 (about 25 cents/channel) from a 5V supply (+12 to +7) and use a P-channel MOSFET and pull-down resistor to get CMOS compatible output. 

Or give up and use a purpose-made current amplifier/level shifter.