mbower,
You might want to know the current (amps) capacity of the charging system before you size your inverter, if you were to go that route. I am in the process of figuring out a way to put an external alternator and battery on a LT to handle the load the inverter I have in mind will put on it. It involves re-arranging the exhaust system a little dab to put the alternator up front and run off the mower deck PTO. The charging system on that little LT could no way handle the 800 watt inverter I have in mind (thats about 66 2/3 amps or so at 12 volts in a perfect 100% efficiency world). So, I am going the external alternator/battery route. I know that the Kubota would have a much larger capacity, but it is still something to consider if you want any kind of duty cycle it would seem to me.
Good luck,
Kurt