I trust you mean brokers that don't charge you financing when you hold positions overnight right?
No I don't know any and you don't want that either - if a broker can't make money from your trading it will go bust. But I do know one that charges financing on the actual amount you borrow and not on the full market position. You should avoid trading with any brokers that charging you over 3% over libor in financing charges. I believe Spreadco also doesn't charge for holding short positions overnight but its only for short positions.
Ayondo [check them out here: http://www.financial-spread-betting.com/spreadbetting/Ayondo-compare.html ] charge 2.5% financing but more importantly they only charge you on the amount you actually borrow unlike most other providers. So say if you go ahead and open a trade for GBP5,000 and put up GBP1000 to open that position and leave the position overnight, Ayondo will only charge you interest on the 'net' GBP4,000 you actually borrowed from the broker and not the full GBP5,000 [most brokers will charge you on the full GBP5,000 and I don't think this is fair]
