Yes, the wafer prober test jigs and delicate analog voltage test jigs scanners we use are all latching relay only. The problem with FET's is you always have leakage onto the common bus - and when you sum up 50 or a hundred or more switches the FETs can be useless depending on what you're doing - especially if the scanner box gets warm and FET leakage goes up. A latching relay is great isolation from the power supply as well, and an open metallic contact is about as good as it's going to get for a true "open circuit", and typically you'll get less Voffset error in the long run.
So look at how many channels you're going to use and what effect FET leakage at whatever voltage - that might make a difference on what you need. I'd just use latching relays though to be safe. Relays are pretty forgiving on voltage levels, polarities, pulse currents etc.
Don't forget that if you're using your switched guarding system typically you'll have 3 switched circuit poles per channel, not just 2.