It's not generally recommended, but you could also try using 3rd party drivers.
For example, the free ASIO4ALL driver-wrapper tries to make available whatever audio hardware is connected to the computer, so it's possible you could use it rather than the native drivers.
I also know that Presonus used to make a big deal about how you could daisy-chain their Firepod/FP10 units, and also their Inspire units. However, those were all firewire devices, so technically daisy-chaining was part of the interface spec.