I talked to the AJA Support people a couple of weeks ago about a time frame of the newer Leopard drivers, they told me that the 3.0 drivers would work just fine with Leopard, that their interface wasn't Leopard ready.
So with noting to do on Friday night and I took the plunge to see. Well the bottom line is, they were correct. The AJA IO LA and IO work just fine with the existing drivers, under Leopard.
My Leopard upgrade went well and only two small applications, didn't work. That is pretty good, I would say. So the machine seems quicker, G5 Dual 2.5GHz w/8GB RAM and 3TB of disk space.