Up here, zippered ski and snowboard bags are the business. I use a ski bag - cost next to nothing, can take serious abuse without falling apart and holds around 10 kites, which is plenty - I almost never fly more than 3 of my own kites during a session anyway.
It also has no ski manufacturer logos printed on it, which is nice. I get enough of the "Heading to the Alps?" questions as it is.
Roll-up bags are impractical for kiting. Always full of sand & snow, have to be opened fully to extract one kite, etc etc.
Juha [/i]