Here is the recipe from Karen's Cookies. I too have been looking for something that works like RI but taste like Toba's Glace. I hope this is it!
Meringue Powder Buttercream
1/3 cup water
3 T. meringue powder
1/2 cup shortening
5 1/2 cups powdered sugar
1 tsp. vanilla extract (use clear vanilla if you want a pure white icing)
1/4 tsp. almond extract
Beat water and meringue powder until stiff peaks form. Add shortening, sugar, and extracts and whip for 3 minutes. Store well covered.
Note: I have had a lot of problems with tiny lumps in this icing, which prompted me to experiment to see if I could eliminate the problem. My theory is that the lumps were being caused by the meringue powder mixing with the water and then drying on the sides of the bowl. So, what I came up with is this:
Sift half of the powdered sugar with the meringue powder, and place in the bowl of a large mixer. Turn on mixer (use whip attachment) and, while mixing the sugar, slowly stream in the water. Let it mix, until everything is incorporated. Avoid scraping the bowl down if you can. When stiff peaks form, add flavorings and mix well. Then add remaining powdered sugar and shortening and whip for 2-3 minutes more. Hopefully you will have a lovely, lump-free icing!