sippy cups, etc

is it possible at all for someone to develop a sippy cup or straw cup for learning toddlers that 1) actually does not leak, 2) has a valve that is easily removable AND cleanable and easily put-back-in-able, 3) will not develop unremovable gunk if a drink stays in there as long as it actually takes for the child to finish the drink?
like all of those things, not just one of them.
argh!

just got the "nuby" straw cup, and the whole valve combination thingy is so irritating to take out and put in - i need extra tools just to get it right, because if i don't get it just right it leaks. it's great when it's put together just right though, but i gotta get this kid on a proper cup fast, because i only started using the nuby yesterday and i am already sick of cleaning it... meanwhile i had to throw out one of the gerber handled sippy cups i had, and yes folks, i did clean it regularly, but the milk he drank left this weird hard, rash-like residue in the inside corners of the soft sippy spout part which are literally impossible to clean...