Anyway, I think the difficulty depends on how you make the swords, how long you'll be wearing the costume, and where you'll be wearing it. For example, I know at Otakon there's one main hallway that gets pretty narrow (because the escalators cut down through the middle). If your convention has narrow hallways, or tends to get really crowded, I'd say it'll be pretty darn difficult. You can always just do Ikkaku without the swords for most of the day, and bring in the bankai for photoshoots, masquerade, etc.
Also, you are my hero. I love people who cosplay Bleach spoilers, and I *really* love Ikkaku's bankai.
And in case anyone asks... here's a reference http://en.wikipedia.org/wiki/Image:R...3;zukimaru.jpg