I honestly have never reached 16 ins/outs limit on the switchblade.
Anyay, consider that the limit is just on the connections available on the sound card of your choice.
Well, talking about ins and outs: with the ff400 I have 8 analog, 8 adats and 2 on spdif, which makes 18. If I use my ff800 I have 10 analog, 16 adats and 2 spdif which makes 28. But you can even have a setup with more audio cards or use separate converters to have the adats channels available as analog.
As you know the software doesn't have limits in itself (theoretically) , the limit is in the capacity of your computer's ram and cpu but now they ar so powerful !