Setting Up Free Email Service And Storing Mails In MySQL

I have a busy dating website with 30 000 registered users and ~200-600 users online all the time. I would like to offer free email with ~10 MB mailbox to all users.

I have an idea to use scripts provided by b1gmail.de. Its similar to Hivemail or Socketmail. It uses only one POP3 catch-all mailbox and stores all emails in MySQL database, including attachments.

My worries are about MySQL. If I have 30 000 users and each user has some 5000 messages in his/her mailbox:
30 000 x 5 000 = 150 000000

That's 150 million rows in one table!

I know, not all users will have 50000 messages in their mailboxes, but the number of users increases about +2000/month.

I can't imaggine how long time will need MySQL to find messages for each user in the table with 150 000000 rows.

I don't know - maybe it's not a problem at all. I just never had such large tables and I don't know if it's possible at all.

Another problem: I have Fedora Core 2 installed and even don't know yet if it supports files larger than 2 GB.

Maybe it's better to set-up normal POP3 mailboxes for all users instead of using one catch-all box and storing data in MySQL?

do not post warnings about spammers. In the beginning I'll provide email addresses only to "gold" members. I opened this thread because I don't want to set-up a system which will hang after a couple of months because MySQL will not be able to handle it or I will have other unknown problems.