Many of these specialty drinks use proprietary premixed drink bases that employees measure out for the various sizes. This makes giving you a recipe pretty much problematic. You wind up having to experiment how to best duplicate the taste that you find in a particular menu drink.

Having a good blender is key to most of these preparations. If you want to use what they use there, buy a Blendtec blender.

So in my experience, the key to a good knock-off frapp is two things:

1) a really really good blender - I use a VitaMix, you could also use a BlendTec

I tried using my old Oster blender, and it's just not the same. It doesn't break the ice down into small enough pieces to get that velvety, milkshake/smoothie-like texture. The texture is a large part of the frapp "experience" and it won't be right if you don't use the same type of blender.

2) Xanthum gum. I get mine from the baking aisle at Whole Foods - it's about $12 for a bag with a cup or a cup and a half in it. I use it up 1/4 t at a time, so one bag will last a really really long time.

Here is a recipe for a homemade frapp that is a pretty good imitation. For a mocha frapp light, you should sub sugar-free chocolate syrup for the sugar and experiment from there.

My shop's knock off is as follows: take whatever cup you're using and fill it with high quality ice cubes. Fill half the remaining volume with cold pressed coffee, fill with skim milk. If you're doing sugar free syrup, add 1 pump (about .5 oz) per 4oz of finished drink; if it's not, use about .75oz sauce to every 4oz of finished drink. Add proprietary powdered mix (this is mostly sugar, dry milk, and stabilizers, in that order) at rate of 1 tsp. per 4oz finished drink.

Blend in a high powered blender for 20 seconds. BlendTec is usually what Starbucks has, but you'll need something similar for the smooth final product.

Tada.