Personally, I wouldn't try and trade Hamilton. With his slow start, his stock really couldn't be any lower. You won't get full value, unless you find a realist manager who knows he'll actually improve.
I'd rather trade some of the higher speed guys you have for some power. Nyjer Morgan and Elvis Andrus both have a lot of hype and may be worth exploring trades. And although I like Ethier a lot, he's been playing a bit over his head. You may be able to trade him for a poorly performing slugger. Also, I'd probably get Dukes in your starting lineup. You could use that power upside over someone like Polanco or Winn.
BTW, if that manager who offered the first trade for Hamilton is willing to overpay with players that will fit your needs better, I'd much prefer it over the first deal.