i live in the city, didn't have a car until this summer and still rarely use it, and can't fathom a reason why you wouldn't be able to use cloth. it's a bit bulkier than disposables, but not so much so that i can't carry it. if you're out for 6-8 hours, that's really only 2-4 changes max. if you use cloth with a nice stay dry liner and the baby hasn't pooped, the diaper will last a fairly long time. i just change, plop the wipe and prefold in a ziploc and keep going. no sweat. if you really have a long day planned with minimal ability to carry stuff, you could certainly use disposables that one day... (i do occasionally myself.) cloth really doesn't have to be an all or nothing game, but really, i think you are over-thinking the complexity of it!
