Hey I have a wedding  cake I'm doing for a client and he said the traditional buttercream  is too sweet and the Italian buttercream is too buttery.... I don't  know what othera to recommend because I feel the Swiss is buttery aswell..  any ideas? I'm  thinking a mousse would be ideal because  it's  fluffy, slightly sweet and feels good on the tongue. Help!!! He's freaking  out 

Ganache?

Cooked flour frosting. In my opinion this frosting is perfectly balance. Less sweet than ABC, and less buttery than IMBC. 

http://leelabeanbakes.com/blog/frosting-filling/even-better-cooked-flour-frosting/

Mix the ABC with an equal amount of MBC.

Years ago in my early days, we used this recipe:

2 pounds powdered sugar

1/2 cup cake flour

1/2 teaspoon salt

1 1/2 cups vegetable shortening

1/3 to 1/2 cup near boiling water

2 teaspoons vanilla

Sift powdered sugar, cake flour and salt together in mixer bowl.

Add shortening and mix on low speed until mixture looks crumbly…the shortening will not be completely blended but that is ok.

On low speed, add 1/3 cup near boiling water and mix until icing comes together.

If too stiff, add an addition tablespoon or water at a time until desired consistency is reached.

Mix in vanilla.

This icing stiffens a bit after it sets...you might need to add another teaspoon or two of hot water or corn syrup to thin for icing a cake.  Stored in the fridge, this icing remains fresh for about a month! 

This icing isn’t super sweet, though you will never know the cake flour is in it either!

This icing crusts very well and makes great air-dried buttercream flowers…just air dry two-three days.

Many decorators around this are still use this icing.  I switched to a butter-based icing a number of years ago just to offer a different kind of cake.

I always add 1/2 teaspoon salt dissolved in 2 tablespoons super hot water to my buttercream.  It cuts down on the sweet just enough.

Cooked flour frosting is so yummy but be mindful that it will not hold up to hot weather ( I can attest to this personally lol) - I have seen one site where they used solite/crisco in place of butter and apparently that holds up in hot weather.

I like this fluffy American buttercream.  My mainstay is SMBC but I use this on occasion when something a little sweeter is desired.  It is essentially part ABC and part SMBC.  The other option as mentioned above is to mix ABC and SMBC in the ratios desired.  Essentially the same, a little less "fluffy".  Both work well.  

http://www.cakecentral.com/recipe/56714/fluffy-american-buttercream

Thanks  everyone ! !!!

salt. salt salt. you can control the sweetness of any buttercream with a tiny pinch of salt. start with small pinch, whip icing, taste, add another pinch if necessary...  until it gets to where the customer is happy with it.

Try out Martha Stewart's basic SMBC recipe! I don't like buttery buttercream as well, but I find this version super fluffy and silky. I agree with using some salt to cut the sweetness :)

Thanks everyone !!!! Another question! I have a smb filled cake with ganache icing how do in store the cake without the smb melting? Wedding is tomorrow at 6 pm and I plan on icing cake around 12pm..

12pm Friday ** wedding is tomorrow at 6pm

Though SMB can sit at room temperature a couple days, I always keep all my cakes stored in the cooler right up to the time I'm ready to box and deliver them.  If the room is fairly cool you could probably get by with it, but refrigeration is the better idea.