I am wondering why you feel your going to get lower armour than a fighter, the way the armour levles and max dex have been worked out, without magical aid on the armour, the maximum starting armour class wiht just armour and dex is 19
Leather is +1 AC max dex bonus +8
Full Plates is +8 AC max dex bonus +1
Almost all armour comes somewhere between those 2 (I think only 2 armour have a maximum of 18, +4/+4 respectively)
Now of course, starting out your highly unlikely to have +8 dex, but most can't afford full plate either, but if I can recall chain shirt correctly, its light armour, +4 armour and +4 dex (18 dex required for full usage) if however you have 20 dex (elf for example) you can go studded leather. Damn I wish I had a book at hand for the correct figures.
If you want to go wiht the heavy armour option, then everyone else has suggested far better things than I could, but as a rogue, I would be concentrating on dex, and even mithril plate will only allow you a +3 dex bonus, meaning base armour would cap at 21, but bracers of armour (+8) dont have any dex cap.
Also remember, you cant be caught flat footed as a higher levle rogue, so you always get your dex to your AC, but touch attacks will ignore your armour, but the armour will still hinder your dex for dodging them
Feegle Out
