Steve:
This is the frosting that Rose Levy Beranbanbaum wrote in "The Cake Bible". (I am a big fan of her!!!) It is used to complement her "Golden What Carrot Ring Cake". She said this is also a "spectacular presentation because it pipes wonderfully". (And it DOES!!!) I use it every times I make that carrot cake. See if it's up to your standard? I really love it!
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White Chocolate Cream Cheese Buttercream
(From "The Cake Bible, p. 237-238)

Make 4 3/4 cups
(1 lb. 10 oz/765 g./ enough to fill and frost two 9 x 1-1/2 in layers or three 9 x 1 in layers)

Ingredients:

3 (3 oz.) bars/9 oz/255g White chocolate (preferably Tobler Narcisse)
4 small packages/12 oz/ 340g cream cheese
3/4 cup/6 oz/ 170g unsalted butter
1-1/2 T./ 23g lemon juice, freshly squeezed

Break the chocolate into squares and place in the top of a double boiler set over very hot water (no hotter than 160F) on low heat. The water must not touch the bottom of the double boiler insert.
Remove the double boiler from the heat and stir until the chocolate begin to melt. Return to the heat if the water cools, but be careful that it does not get too hot. Sir 10 minutes or until smooth. (The chocolate may be melted in a microwave oven if stirred every 15 seconds. Remove before fully melted and stir, using residual heat to complete the melting.) Allow to cool
In a mixing bowl beat the cream cheese (preferably with a flat beater) until smooth and creamy. Gradually beat in the cooled chocolate until smoothly incorporated. Beat in the butter and lemon juice. Rebeat at room temperature to ensure smoothness before frosting. (see Notes.)

Notes: Do not rebeat chilled buttercream until it has reached room temperature or it may curdle.
When using this frosting for a (wedding) cake in the heat of a southern summer, decrease the butter to 2 oz. And it holds up quite well.

Store: 1 day room temperature, 2 weeks refrigerated. 2 months frozen