Is the AD629 the op-amp with the best common mode rejection?

Currently I use the AD629 in a cell voltage monitor (CVM) board for measuring the individual cell voltages in a fuel cell stack with 88 cells. Each one of the 88 cells can produce plus, minus 1v (the minus voltage is the output of the cell if something goes wrong with that particular cell) and all cells are serially connected or the total voltage normally is 88vdc. This op-amp is very good but I still have a question: does AD offer some fully isolated part in order to decouple even better the ADC on my CVM board from the stack voltages, at some reasonable price (up to $10 or so)?

I'll highly appreciate your suggestions!