(P.S. Please sticky me.)
I packaged up all of the known Siege maps into a super huge zip file. You can download it here (only 475 MB haha):
http://www.filefront.com/16368871/allsiegemaps1.zip
CONTENTS:
01) siege_cargobarge
02) h3hsiegeV2
03) siege_h3h2b
04) siege_bomb1a
05) siege_bomb1b
06) siege_warcom
07) siege_theed1a
08) siege_mygeeto1c
09) siege_mygeeto3a
10) hoth_modified
11) siege_usm1a
12) siege_hotfo1a
13) korriball1a
14) korriball1b
15) siege_mine2a
16) siege_mine2b
17) geonosis1a
18) siege_geo1b
19) siege_endor
20) siege_sillyroom
21) imp_raid2_bank_job
22) Imperial_Warehouse_Night_Raid
23) siege_yavin4
24) droidball1d
25) droidball1e
26) eternal_suess
27) siege_endor_bunker (siege_endor_mst_03)
28) siege_endor_village (siege_endor_mst_03)
29) siege_endor_shieldgen (siege_endor_mst_03)
30) siege_destroyer
31) allmaps1_readmes.zip <-- All readmes for the various maps/models/credits
P.S. It's probably not a good idea to put all of these in your base dir at once. The various revisions of the same maps will probably have some file conflicts. This is just every map I could think of out there, in one convenient download. That way you can be sure that you have whatever may be played, and just copy whichever maps you choose into your base.