I wonder if anyone would be interested in creating a whitelist of publishers that treat postgrads and ECRs properly, as opposed to the disdain and rudeness that I've seen from some? I would create a blacklist, but that would probably result in me being blacklisted myself!

I would be interested in seeing such a list and happy to contribute when I start submitting work to publishers but I can't help at the moment.

I'm the same as Aisling in that I'd love to see a list, but currently have no experiences I can contribute. Sorry :(

No worries :)
I will contribute my own experiences so far shortly. I'm thinking about doing a survey on ECRs' experiences with academic publishers.

I'm wary of suggesting anything that lends itself to tokenism, but does anyone think that academic publishers should have a code of practice for dealing with ECRs?

I think the problem you and other recent PhDs are having is that the publishers need to make money, and monographs from PhD theses don't tend to sell well. Offer to write a textbook and it would be a different matter. The only people I know who got their thesis taken on by good publishers were introduced by their very famous examiner / supervisor and touted as geniuses. I can't see how you can force businesses to publish books they don't think will be profitable.
There are other presses that are receptive to the book of the thesis, but the problem is that they are not the ones with the best reputation - they often operate a print-on-demand service, so their profit model is different, and the copy-editing etc is done by the author, and there's minimal marketing. If a monograph is really the desired outcome though then they are worth considering. Cambridge Scholars Publishing have published the theses of a couple of people I know. Ashgate and Peter Lang also still seem open to theses. Sorry I only know the social sciences ones. Critically though, these were people who didn't want an academic career, so press prestige didn't matter, but they wanted a book out of their PhD experience. If an academic career is the goal then journal articles are probably the way to go. Pick journals that do blind peer review and then the ECR status is irrelevant - mind you you're still going to get knock backs and nasty criticism, but it is a more meritocratic route.

Of course the decision to publish monograph is a commercial one, I don't think anyone would suggest that there is a right to have your thesis published! Peter Lang doesn't have a very good reputation does it?