Hmmm, 16 weapons per unit...now there's an idea. But we're short on actual units so someone get making. Here's a good idea for a unit that you could make:
Type: Land/Aerial (this may not be possible, but you can try)
Tech Class: IV (built by Gantry, if that's there)
Race: Arm (since it's high-tech, and Arm have that advantage)
Weapons: #1 Krogoth Guided Rockets (from the Krogoth obviously)
#2 Annihilator BLoD (from the Annihilator - duh!)
#3 Twin THLs (Twin Heavy Lasers and no it's not a typo - it's like Medusa)
#4 Twin Rapid Flakkers (like the Fury)
#5 Twin Super AA Missiles (like those of the Mercury)
#6 Twin Rapid Gauss Cannons (like the Krogoths, except much faster RoF)
#7 Main Cannon (this will be the Orb from Rumad or equivalent power)
#8 Twin Vulcan Cannons (only 20-30% of the range and power though)
#9 Twin Super-Rapid Light Laser (like that of the Orion)
#10 Twin Tachyon Cannons (like those of the Vesuvius)
#11 Rapid-Fire Plasma Cannon (like the Arch's only faster RoF and more powerful)
#12 Twin Karganeth Proton Infusion Warheads (the Karganeth's longest-range weapon)
#13 Twin Karganeth Spray Weapons (the Karganeth's short range anti-group weapon)
#14 Twin Twin Karganeth Cannons (the Karganeth's long range main weapon that seems to fire through walls btw - maybe that's just cos it's such a tall unit?)
#15 Quad Super Torpedo Launchers (like those of the Adv. Torpedo Laucnher only there's 4 of them - eat that nasty subs)
#16 And finally, a weapon that specialised in destroying super units so that it does massive damage to them (need to make a new one). Failing that you could equip a rapid-fire paralyzer, a field-of-effect paralyzer weapon (like that of the Stasis), or something like that.
That's all the weapons. Now for some details on the unit. It's type is Land/Aerial, because it can fly, however, when flying, its weapons (at least any that AREN't total AA-based) should be disabled. When it lands, its land (and sea) weaponry should be brought online. Placing the unit into/out of flying mode should take some time - i'd say a good time is 30-60 secs, during which, the unit is vulnerable to attack. Well, by vulnerable, i mean it can't counterattack (except against aircraft). This operation cannot be cancelled so be careful about placing it into and out of this mode, because its shields are brought offline while in transit (should be).
The unit should also have XLR radar and sonar, and should be able to detect cloaked units except Commanders (if this is possible in the game). Oh and did i mention - it shoud be shielded (way better than the Orcone's shield, and shield should come offline after suffering about 80% max hp damage)? Cloaking would be a fun thing to add, but that would make it just too unfair to the other side(s) so i'll recommed not including that. It should be invisible to radar though.
What else? Well, it should be a rather large unit (at least 50% than ol' Kargie, since it has lots more weapons, and is one heavy sheit). This mass (and therefore weight) will have an impact on the amount of energy the unit will use to become airborne and stay airborne. Moving in the air requires even more. Also, if possible, the gravity of the world should be taken into consideration since less gravity means less energy to get in the air and stay there.
If this unit gets implemented, i'll leave it to you to work out the energy/metal costs of firing weapons etc, but i'll give an estimate "good" cost of the unit:
Metal: at least 450% of the Karganeth (>= 313141MU)
Energy: at least 1200% of the Karganeth (>=6561096EU)
Built Time: at least 1000% of the Karganeth (>=10496470BU, which is equivalent to approx. 7h 17m 20s at 400BUs - the Gantry's speed)
The reason it should take so much resource and time is because Arm now have the advantage, if given the time to build this monstrosity. Core beware, since this would rip and army of your precious Karganeths to pieces, while only maybe suffering a few paint scratches. That is, assuming it is implemented as specified here (which it probably won't be able to due to certain difficulties that will no doubt arise).
Anyway, to end this ever-so-long post, i shall finish with the unit's name. And that name is: Black Bahamut (partially named after, well, you know, the King of the FF Dragons, for which, i have to credit Squaresoft - now Square-Enix).
So long, and c'mon, someone else get those 16-unique weapon unit specs rolling.
(Wow, my fingers ache. No wonder, you're post is long enough to qualify as a (best-selling lol) novel.)