Plate carrier for small frame?

If it does not need to be quick release, the Mayflower APC in S/M with the small cummerbund is very good and wears well.

LBT 6094 is a decent quick release with some other neat features like a better cummerbund with MBITR or magazine pockets, but I did not think it rode quite as nice and it is significantly more expensive.

Probably anything else with small/medium plate bags and not much extra frontage with a lot of cummerbund adjustability would be fine.
 
Extra small surplus iotv's are abundant and cheaper because they don't sell. They also fit small plates and some will fit a medium.
I preferred a small itov with large plates even tho I fit just right into a medium.
Much more comfortable that way and to me the bigger plate for some reason held firm in the smaller iotv gave me more movement. The medium plate seemed to stick out off my chest a little more and the corners were noticeable with movement.
They do however suck without the soft armor and just plates. I only got $100 for my ucp (digital camp) iotv in like new condition. I picked up the newest version for $250 like new.
 
Crye JPC 1.0 sized small...IF you have Small ESAPI plates. The medium would probably even work, but only if you have medium ESAPI plates.

If you aren't running ESAPI cut/spec'd plates, then don't go that route. Another option is a small Ferro Slickster or the Spiritus LV119 (overt or covert model, depending on your needs). If the 6094 is too much, then I'd stay away from the other styles that are out there and just give one of these a try (plus they aren't that expensive and maintain value if you get it and realize it doesn't fit).