Ells value right now could easily get us a solid return. Not a "big haul" per say, but a quality return.
His value at the deadline, like ive said before, depends on the team who wants him and the situation they are in.
Lets say Ellsbury is doing very good but the sox arent going to make the playoffs and a first or second place team loses their starting CF without a comparable replacement. They will lose considerable production that wont be replaced. Their need is huge and they might part with a little extra to acquire Ellsbury.
Value depends directly to the need that team has and how great they value that need.
If Ellsbury hits .300 with a .370obp, a near .500 slg, and some team has a big need. we will get something nice back. Its always been that way.
Even without the comp pick a GM is looking at going far in the playoffs or possibly not making them at all and having to hear it from an angry fan base and the promotion side of things for not making a move.