These are "Proof of Concept" maps.
The concept: Team DM through a protective spawn 
(one for each team) that remains until Extreme_Sudden_Death.
Build zones are available through secure reactors 
and secure overminds (by secure I mean inaccessible 
to deconning). The strategy change in this as compared 
to Non-Battle Arena maps is the teamwork involved in 
not only holding off and - once ESD hits - defeating the 
enemy, but also team work for building and structure 
defense to provide the team an upper hand.  To build 
structures such as armors, additional spawns, booster, 
and others will require teams protecting the builders to 
achieve that 
significant upper hand. 
it will be very interesting to see if someone writes a strategy guide for these maps.
file name: 4map-ba1to4_v1.0.pk3
size: approx 10MB
important notes:
NOT FOR USE ON SERVERS WITHOUT EXTREME_SUDDEN_DEATHincludes: ba1.bsp, ba2.bsp, ba3.bsp, ba4.bsp
new shaders and textrues (no all have gtk editer images) include 7 new glass textrues, 1 new water texture, 1 new lava texture, and varous woods, stones, bricks, soils, and dirts.
bonus: source .map files free for tinkering (please share credit on creations or I bitch from hell)
Download Links:
File Factory: 
http://www.filefactory.com/file/955791/n/4map-ba1to4_v1_0_pk3File Send:  
http://www.filesend.net/download.php?f=4fca06ea12eeccd79f81fb3bf8f9101eShare Send: 
http://sharesend.com/q9qlrGameUpdates.org: 
http://www.gameupdates.org/details.php?id=3006