It turns out it's not strictly true that there's no disclosure of who the donors to the William J. Clinton Foundation are. The Clinton Global Initiative, one of the Foundation's branches, posts a list of members and the "membership fee" is $15,000 a year. It's a pretty long list, and mostly either of people I haven't heard of and those I have heard of range from Brad Pitt to John Podesta and back. But also Denise Rich, Marc Rich's wife, who I would have thought the Clintons would be going out of their way not to associate with or at least take money from at this point.
Of course, this sort of thing is still a poor substitute for real disclosure of who the donors to the Foundation -- and to other presidential foundations like the one George W. Bush is putting together as we speak -- are and how much they're giving.