Originally Posted by mamafrogcakes

Hey Squirrelly, what about just putting it in the fridge since it usually gets so hard from the butter anyway?? Hmmm....

Well, the Italian would hold up better likely. Not that these icings on their own cannot be frozen because apparently people do, my concern would be when they defrost how well the colours would hold up, if they would run.
I don't know of anyone that does this but you know, that doesn't mean that it cannot be done in some cases. I think I prefer to use the standard American buttercream icing for a transfer because a cake with such a transfer can sit at room temperature for days. The Swiss would have the least desirable results because it does tend to deflate somewhat and is not something that holds up well at room temperature and is most affected by humidity changes.
I like to freeze a transfer because they are easier to work with in my opinion. Also with standard buttercream, I don't have to worry about using pasteurized egg whites or meringue powder because of any risk of salmonella poisoning. I find regular buttercream takes the dark colours well.
But hey, why not give it a try and see if you are happy with the results.
I must admit I have never tried to colour these types of icings with really dark colours, I cannot see getting a black for an outlining but... I have ever only used a pastel with these icings.
Hugs Squirrelly

Yes, good idea, and I would put some colour into bits of it, put blobs of coloured icing side by side and see what happens once after a day or two in the fridge or freezer. You are looking to see if the icing will colour, if it will bleed and how it will hold up.
Hugs Squirrelly