What I do is that you can put buy offers from your main (for 1gp ea), and accept from your noobchars. This way you can also launder money if you dont want to directly transfer money to them. If my noobchar needs 200k and he has 1000 items to sell I can put buy offers on them for 200gp each. Your main will get the items when noobchar accepts, and noobchar will get money through market, which is way more secure tranfer in terms of multiple account-deletions.
This would give you the items sorted and ready in your main chars inbox. But yes, you'd have to withdraw them yourself, either manually or by script, if you sell to NPC. To market you can just put them directly from inbox at your main char.
Anyhow, no there is no restriction about how many pages. I think there is a limit of # items however, but you should not need to worry about that. We dont support backpacks at this time, and probably wont add either. The effort to get around this problem is relatively low.
/Stusse