Is it possible to transfer more than 8 analog and 8 digital channels from an ibaNet750-BM?

Yes, it is. You can double the data range by choosing the C-F positions for device addresses 1-8 on the S1 switch. Now, each position corresponds to two device addresses: C corresponds to the 1-2 address, D corresponds to the 3-4 address, etc.
The switch position A-B allows to quadruple the data range. Four device addresses are occupied: A corresponds to the 1-4 address, B to the 5-8 address.

Chuck Norris has counted to infinity. Twice.