WoW betas - timeline

I found interesting information about the official "press-release" dates of the Betas so far (starting with burtning crusade, wrath of the lich king, cataclysm and now mist of pandaria) at wowwiki.com

A closed beta test period was announced on March 20, 2012 with invites going to Annual Pass holders, press, fansites, friends and family, and opt-in beta testers. MMO Champion may have gotten access soon after the opt-in announcement and an official announcement of the start of the Beta was released late March 21st, 2012.
Level 85 Monk premades were made available on April 8th, 2012 (likely in Patch 5.0.1 build 15544).

Servers
The servers were split into the following:

• Lost Isles (US) - PvE
• Gilneas (US) - PvP
• Hamuul (KR) - PvE
• Mekkatorque (EU) - PvE 

Text from http://www.wowwiki.com/Beta#Mists_of_Pandaria

Also... fuck yea! I'm mentioned at that page :D (No, I didn't wrote it on my own)

Timeline: WoW client builds information

World of Warcraft Final builds information

World of Warcraft - Vanilla (Alpha)
6005 Version 1.12.2 (6005) Oct 13 2006

The Burning Crusade
8606 Version 2.4.3 (8606) Jul 10 2008

Wrath of the Lich King
12340 Version 3.3.5 (12340) (Release) Jun 24 2010
(a.k.a. 3.3.5a)

Cataclysm
15354 Version 4.3.3 (15354) Feb 22 2012
???? Version 4.4.0 (????) TBA

Mist of Pandaria
15464 Version 5.0.1 (15464) Mar 17 2012
15508 Version 5.0.1 (15508) Mar 26 2012
15777 Version 5.0.1 (15777) Apr 1 2012
(don't ask me how, but i first got the 1. April update and then the 15554 update)
15554 Version 5.0.1 (15554) Mar 30 2012
15589 Version 5.0.1 (15589) Apr 6 2012
15640 Version 5.0.1 (15640) Apr 22 2012