You don't need to spend a dime to prove or disprove whether it will work for yourself. You can do it entirely on paper. Take the specs of your LEDs and the specs of the LED Intruder and see if it will handle the loads you proposed. Of course, you should do this kind of analysis before buying ANY product or component.
I think the LED Intruder is a great product. But it just doesn't appear to fit your original requirements. Or maybe you can change your requirements to fit the LED Intruder. Only you can make that kind of trade-off decision because you know the project and we don't.
My intent is not to "poo poo" you. I am just suggesting that you do the calculations before getting excited about anything.
I think there is some ambiguity in the OP's requirements. If the intent is to run 10 LEDs off of one output channel, well, that's not gonna happen. That would fry the LED Intruder pretty quick (been there, done that). If the intent is simply to control LEDs in banks of 10, that's not a problem. The OP could wire one set of 10 LEDs to one LED Intruder, 1 per channel, using one LED Intruder per bank of 10. Using the formula on page 11 of the manual, 10 LEDs drawing 20mA @ 12V will consume 2750mW of power, well below the 3958mW hard limit. (16LEDs, however, is too many. Just FYI). This of course assumes that the OP has soldered the heat pad underneath the chip to the PCB. If the heat pad hasn't been soldered down, the hard limit will be a good bit less; if the OP breadboards with a DIP package, the hard limit is less yet, and 10 LEDs may be too much at 12V.
In which case, perhaps the OP ought to reconsider the 12V power supply, and go for something lower. A 5V supply would probably be just fine for this application.
Don (creator of the LED Intruder)