For most of the AC series, I've tried to style my AC around the Tallgeese 1 from Gundam Wing. I always thought it was the most interesting Mobile Suit of the Gundam universe, even if it's not an actual Gundam.
I read quite a few creation guides for making Tallgeese, but I created one that I think would be more practical in terms of how it performs in the series:
If you can't be bothered with looking at the images, here's the specs of this build:
Pilot - Riko AC - Talgeese (it's all I could fit) Parts: Head: HD-4004 Core: XXA-S0 Arms: AN-25 Legs: LN-501 Generator: GBX-XL FCS: TRYX-QUAD Boosters: B-VR-33 No Back Weapons Arm Weapon L: LS-2001 Arm Weapon R: WG-B2120
Optional Parts Equipped: SP-JAM SP-ABS SP-CND-K SP-S/SCR SP-E/SCR SP-E+ SP-DEtq (Note: don't have the best dampener as of this writing, otherwise this might be different.)
Color-wise, I had tweaked it left-and-right to try and get the best colors I could, but it's not 100% likely to be accurate (I pretty much suck at color schemes, and coloring the head crest would make it look stupid):
Each section has the XX/XX/XX for the RGB color in order: Base, Optional, Detail, Joint: Head: 50/50/50, 40/40/40, 07/07/44, 07/07/07 Core: 51/51/51, 16/16/16, 51/51/51, 27/27/27 Arms: 51/51/51, 16/16/16, 07/07/07, 27/27/27 Legs: 51/51/51, 51/51/51, 07/07/07, 27/27/27
What I'm posting is not exactly what I use in the game, as each scenario and mission is different, but for the majority of the arena matches, I use the moonlight and usually a handgun to stun harder to hit enemies. My own build is meant for high speed strafing and close-up blading.
At first, I meant to use the moonlight as the blade, but the LS-2001 looks more like the saber Tallgeese has in the anime. I also meant to use the Shell-based Slug Gun as the weapon of choice, as it looks the closest of any gun to the rifle Tallgeese has in the series, along with it being shoulder-mounted, but decided on the bazooka due to faster reload, better damage, lighter weight, and it's ease-of-use for non-Plus builds.
Used the 4004 head instead of the other one due to preference, and it's easier to color the eyes (personally I had used the HD-ONE for all 3 games, but changed it to this one due to MoA not having any need for a Bio Sensor).
Everything is more or less meant to make the AC lightweight, as the Tallgeese was pretty much a light-weight close-combat type when not using the rifle. Also, the optional parts are used to make the build as energy-efficient as possible for non-Plus builds as it can, although personally, I have all the Human Plus additions, as well as the overweight status, but prefer to make something that's obtainable if this is a fresh start with no previous game saves.
Well, those are my specs (at least for my version of a Tallgeese build), so if anyone is still lurking around here, I wouldn't mind knowing what others use or think works well.