[Dovecot] Gmail like virtual mailboxes

[Aleve Sicofante]

I'm new to this list so let me introduce myself: I'm a computer
literate user (I've done some C programming long ago and can run a
Linux system and do some light admin), I've never installed a mail
server before and I'm in the process of migrating my family and my
small business from Gmail (Google Apps) to a virtual server mainly for
privacy reasons. I'm in love with Gmail's label system and I just
plain hate traditional folders. I use hierarchical labels (as if they
were folders but with a message belonging to many at the same time)
and that MUST be preserved in the migration. I've looked at Courier's
IMAP keywords implementation and it looks good, but everyone on the
internet is recommending Dovecot, so here I am.

I've tried hard to find information about using unlimited hierarchical
labels, virtual mailboxes or any other way of mimicing Gmail's
functionality with Dovecot, but I'm lost.

First of all: can it be done?

If so, is there any introductory documentation? (I've only found very
sparse information.)

Is it available for any storage format (mbox, maildir, dbox)?

Any help will be very appreciated.

--
Aleve Sicofante