Here is one model I have done which you are welcome to use. It's my version of the blue arcadia. I reworked the textures a little bit today to make them a little better. It's a little large on the triangle count (10-11k I think) and could use some trimming. I'm am by far not an expert when it comes to modelling or texturing as I only started learning modelling around this time last year and texturing this year so judge it by those standards please.
Maybe someone called Genocyber will contact you... He have begin a mod based on Japan Anime... I have already give him my green Arcadia... sure that he will be pleased by your blue version...
In my case, the model is two year old, was made in begin for the Tri-pirate mod who is now dead... Around the same amount of poly that you ( 11-12 k tri )
Have screenshot only from the first texturing... made before sins switch the cl alpha with the da red... a new texture was created after...
For these who have interest, model can be found at : http://www.love-from-russia.be/arcadiaUV.obj
Like you, my modeling and texturing skill have evolve to become a little better... my last finished work is for the Halo mod... 4 ship using one single texture set...
The screenshot below is using the original texture file in tga format... it is the civilian version of the phoenix around 8k tri...
The next one is with the civil version on the top and military version down... military version is around 15k tri... was a test of the maps in dds format but with raytracing render...
There is a frigate/cruiser model too, around 1k tri and a 96 triangles model ( pic below ) being the trade ship model... on huge multistar normal sins game, these are so numerous that they slow down the game after playing a few hours... very low poly was needed...
Polycount of capitalship is not so important because each faction can only have a max of 16 of them... but little thing like tradeship, refineryship, fighter/bomber, and planet elevator can become numerous in late game and eat a lot of poly...
Anyway, the main problem in sins is memory... and since the 4 models are using the same texture map, a lot of ram is spared...
Working on a bunch of other models but i will not post them all here... was only because i have reply to your Arcadia post that i have use the same post for show my last model
EDIT : for ingame screen of the phoenix : http://www.moddb.com/mods/halo-sins-of-the-prophets