Huge Maildirs?

[List Monkey]

Does anyone have experience with HUGE Maildir's?  I have an account that
is subscribed to a lot of high traffic mailing lists (like this one), and
I want to keep all the messages on my server.

I have seen grumblings, but no concrete info, on what may happen when your
Maildir contains 10,000 or 100,000 or 1,000,000 messages?

I am running 2.2.* Linux

Thanks.