If you can not get Satin Ice in Canada, then I would make MMF and add Hersey's Special Dark (Dutch Processed) Cocoa to it. You will get black!
Here is the link to the thread....
http://cakecentral.com/cake-decorating-ftopict-34064-mmf.html+turn+black
HTH
I think it would last forever......well as long as you have the mmf. 
Make sure it is Dutch Processed. It is a special cocoa. I called four stores before I found it. When in a pinch I use MMF and have used the cocoa otherwise it is straight Satin Ice for me.
Good luck and btw thanks for the compliment. 
Tiptop57, thanks so much for the advice and the link, that is GREAT! I guess I'll start making batches of whole colors. I take it fondant lasts for months in airtight ziplocs?? Thanks again so much!
Christie
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