Im thinking in equip my main companion with pvp gear, since i have 1000 century comm. What its the gear i can buy ? The companion in question is Mako.
The only issue with putting pvp gear on companions is some of them use odd weapons stats that aren't reflected on pvp vendors. What you can do for them, is get a moddable weapon, buy extra pieces of appropriate stat gear (say cunning gear), pull the mod and enhancement, and put it in the moddable weapon(s). Run dailies for daily comm's for the hilt/barrel, buy a crystal from the vendor (that will be going away in 1.2), and you're all set.
I've got Jaesa in full centurion stalker gear with a fully purple 51 double saber. She tears things up nicely now.
Gearing up companions (Empire-side):
Mako: Imperial Agent (Blaster Pistol)
Gault: Imperial Agent (Blaster Rifle/Sniper Rifle)
Torian Cadera: Bounty Hunter, but uses Techblade/Techstaff/Electrostaff
Blizz: Bounty Hunter (Blaster Pistol)
Skadge: Bounty Hunter, but uses Vibrosword
Khem Val: Juggernaut, but uses Vibrosword
Andronikos Revel: Imperial Agent, uses Blaster Pistol as mainhand & offhand
Ashara Zavros: Marauder (dual Lightsabers)
Tallos Drellik: Imperial Agent (Blaster Pistol)
Xalek: Sith Assassin (Doublesaber)
Kaliyo: Bounty Hunter, can use Blaster Rifle instead of Blaster Pistol
Vector: Sith Inquisitor, but uses Vibrostaff
Doctor Lokin: Imperial Agent (Blaster Pistol)
Ensign Temple: Imperial Agent, uses Blaster Pistol as mainhand & offhand
SCORPIO: Bounty Hunter and/or Droid Parts with Aim, but uses Techblade/Techstaff
Vette: Imperial Agent, uses Blaster Pistol as mainhand & offhand
Malavai Quinn: Imperial Agent (Blaster Pistol)
Jaesa Willsaam: Sith Assassin (Doublesaber)
Lieutenant Pierce: Bounty Hunter, can use Blaster Rifle instead of Blaster Pistol
Broonmark: Juggernaut, but uses Vibrosword
So, every companion has a good set of gear to utilize (with SCORPIO being able to mix Droid Parts with armor, apparently) and the large portion can simply use purchasable weapons, though you may get better mileage on some by completing one of the two Heroic 4 daily missions on Belsavis, as it awards a Customizable weapon for any of your companions, aside from the ones whose weapons can't be made custom (Techblade & Techstaff I think); the non-customizable ones are Blue-quality, level 50 weapons however, so they may be helpful still.
is there any decent vibroswords as you're leveling up? having trouble finding any for khem val, i'm at like 27 and he's still rocking some level 13 green.
Nearly every quest offers you the choice of a piece of gear for you, a planetary commendation, a random item box, or COMPANION GEAR, including weapons. If he's still using a level 13 green, it's because you've either skipped quests or passed over Khem's weapon for something else multiple times. I know my Khem has upgraded his weapon several times via quest rewards and I didn't even pick his weapon option every time it was available.
I know I bought a Custom Vibrosword for Khem on Dromund Kaas for Commendations.
Planetary Commendations are another nice spot to look for custom weapons for companions as well. Kaas, Taris & Voss all have custom weapons available, and Nar Shaddaa, Belsavis & Corellia have custom offhand weapons as well.