It depends on just HOW light you want to go.
I pretty much always wear light armor and spend a lot of time in the battle server. In my experience, the byrnie and lamellar vests are just about the perfect balance. Body armor is the most important armor stat, so don't be afraid to get something on the upper end of light. Even a tunic over mail would work, although that's really getting more into the medium armor range. Pretty much any gauntlets work, since they're so light. In fact, when I want to roll a little heavy and survive to the end of the round I usually take some wisby gauntlets, or even my heavy gauntlets, to boost me into 40+ total body armor. Of course, regular leather gloves are fine too, especially if you're going for high speed.
Head armor can be helpful, although personally I don't bother with it when I'm going light. A straw, felt, or fur hat for style, maybe. If you want some head armor, you should stay below the mail coif, which is 0.7 weight. I like the steppe cap. Boots aren't really important, so feel free to skimp. I like taking the turkish shoes, since they look nice and are 0 weight, although anything up to the rus cavalry boots would work.