Blendtec. It is a little on the pricey side for home use, but you will not be disappointed. It is what we recommend to all of our clients. If you decide you may want one, PM me or email me on the coffee site and I can get you better pricing than what most are selling them at.
Best pina colada mix is to not use a mix. Buy a can of Coco Lopez and a can of pineapple juice, and follow the instructions. If you use frozen pineapple chunks instead of juice, you can get a thicker drink without diluting the flavor as much.
Sub lime juice for the pineapple and make a very tasty coconut daiquiri.