It's been said before, but to so-called cel books
you would consider are very common from many 
places. :) Itoya sells an archival scrapbook that 
is quite cheap at well-stocked art stores. Other 
things like bags, just do more research..

Click on the link above to take you to my cel 
supplies guide - there are more points and links 
to many on-line resources and stores. I plan a 
revamp sometime this month (but if people don't 
use it, there's not point! ^_-). I also have a few
cel supply sampler kits left, which you can read 
about here.