Does anyone know of a good protein powder I can pack for a trip I am taking? I thought it would be easier to take a powder and a mixer cup that I can just keep in my purse, instead of worring about my EAS RTD bursting in my suitcase.

EAS does package their original powder in single serving envelopes, probably the most convenient way to carry it.
http://eas.com/product/myoplex-original-powder