Back in AD&D (2e), the brigandine had these stats: AC 6, 120 gp, 35 lbs.
If we were to convert it in 3.5/pf it'd need a bit of tweak, since converting "as is" would result into something nobody would wear.
I mean, by translating stats directly, you'd have , AC +4 120 gp 35 lbs. (which makes it same protection, heavier, and more expensive than a chain shirt). Not sure about max dex, but there. Maybe similar to a scale mail, make it maybe a bit cheaper, class it as medium armor and it's set.
Also, somebody did this for 5e
https://sefotron.blogspot.com/2015/0...-armour_7.html