I promised to report back after using the homemade marshmallow fondant and here are my thoughts on it:
At first I thought I was going to love it; it looked nice, it felt better, it tasted AMAZING, but it was extremely difficult to handle. I'm thinking now that it could be because I only used half the amount of sugar called for in the recipe but it was beginning to dry out with the amount of sugar I had put in. Oh well, that will be my next experiment. The biggest problem I had with this was trying to roll it out WITHOUT it sticking to the counter top. It didn't matter how thickly I coated the counter top with sugar kept sticking, ripping, and needing to be re-microwaved. Finally I used a thick layer of Crisco to coat the counter, that worked wonders! All in all I guess I'd try this recipe again and use the full amount of sugar in the recipe, but for important projects I'll stick with store bought fondant :x.