Board that only plugs into balance port and balances cells automatically?

Having had a lot of frustrations with my bms not doing what it should, and the fact I only charge through the bms, it would make more sense to get rid of the bms, and use something else to balance the cells. Is there such a product on the market that you can plug into your balance leads, and it balances through the balance leads the cells by passing the voltage around.

for example, say you have a 6s battery whose cells are at: 3.5, 3.8, 3.9, 3.5, 3.9, 4.1. Just leaving this plugged in, it would move the voltages around to balance them to all 3.7 (which is the average).

Does such a thing exist? And for a 10s?

http://www.hobbyking.com/hobbyking/store/_10328__HobbyKing_8482_Battery_Medic_System_2S_6S.html

only ten shmoos if you wait on the page doesnt average but drops all to the lowest. theres a bunch of versions of this but I’ve never seen anything beyond 6s.
they also can have issues with too much current and you can get one with attachment bulbs.

I’d like to see if someone can make one for 12s!!!? I dont need a screen