I recently decided to try making my fondant from scratch rather than using my favorite, Satin Ice.  I tried marshmallow fondant first and it was ok but the texture is not what I am used to using in Satin Ice.  It was a stickier texture and I felt I didn't get very much stretch with it.  Next I tried Michele Foster's recipe and when I first mixed it I thought it would be great.  After sitting it was better than marshmallow but tore very easily and had no stretch.  The second batch I made I had to color purple and I added it while in the mixer.  This batch was terrible.  I couldn't do anything without it tearing. When I tried to work it would break instead of smoothing  I had to knead it in small amounts just to get a workable texture.  When I rolled it out  it completely broke on top of the cake. After an hour of kneading I got it on the cake, but them the whole cake has what looks like pot marks over the entire thing.  I have seen so many people rave about both of these recipes and just wondered where I am going wrong. Did I knead in too much powdered sugar initially?.  Did the color change the texture that much?  I added a lot of extra glycerin trying to fix it. I just would really like to get as close to Satin Ice texture as possible  

AWith MMF, color changes the texture especially dark colors. Some thoughts:

1) Add color a shade lighter than you need to MELTED marshmallows. It's my experience that it darkens as it sits.

2) I personally like to let dark colored MMF sit for two days after I make it before I try to put if on a cake.

3) I prefer not to knead powdered sugar in to MMF with my mixer. I find that it gets too dry that way. For me, it's easier to just knead by hand to make sure I get the right consistency.

It's hard to say why your fondant has no stretch. I don't have an answer for that. But I hope at least one of those tips helps!