The SCXI 1300 is not a DAQ device. It's a terminal block. You actually need to have another SCXI module that has analog outputs. There are only 2 SCXI modules that have analog output. One is the 1124, which sells for $1649. The other is the 1581, which sells for $2099. I guess that USB one is looking pretty good right about now. Unfortunately, it only goes to 5V. The 9263 can go up to 10V, but it sells for $639. You may be able to find cheaper alternatives by looking at other vendors, though you'd need to look at being able to use them with LabVIEW.
You could go the variable resistance route. I know there are EEPOTS that can be programmed via I2C/SPI since we've used them in some of the stuff we've built here at work. Don't recall the specific part numbers, though. You can Google for them, or check the major chip makers, like Maxim, etc. You'd need to make up a small breadboard to use it, but you're already dealing with a dinosaur, so it may not be that bad to kludge something up this way.
As for examples, lots of examples ship with DAQmx.
