We need to build a system that, at its core, needs to be a MIMO transceiver: I/Q analog ports (eight ports) at a minimum 40MHz bandwidth on one side and RF ports (four ports: two TX and two RX) at 2.4GHz at the other. The more flexibility we can build into it, the better, that is why we like the AD9361: it gives us the option of 12-bit digitial instead of I/Q ports, it gives us bandwidth flexibility > 50MHz and allows us some options for future expansion beyond 2.4GHz ISM.
We'll have to add custom power supply, RF front end, power detection, PLL, etc. but at the core, if we can get access to I & Q for TX & RX of both streams the AD9361 would take care of the hardest parts of the requirements. Is there an option to mux I & Q out of the chip for TX & RX for each spatial stream?
If that can't be done then I'd appreciate a recommendation of your mod & demod chips (even better if you have mod/demod IQ to 2.4GHz RF in one chip - we'd just drop two of them down to cover the MIMO requirement.) We aren't power or space constrained for this design and I've got plenty of options for the RF requirements, PLL solutions, etc. but it is the heart of the design that I really need to choose carefully.