A colleague of mine, Ian Devlin, put this up yesterday. I’ve had a small play with it and forked it to add some caching. It seems like a pretty good workaround (note, I don’t say solution!).
I’m sure he’d be glad of some community feedback on it. I haven’t really had the time to poke holes in it fully yet, but I like what it does. His article explains in depth what he is doing but in synopsis, he is creating the img source from a php script which can also take arguments for height, width, crop and scale. Tied in with Scott Jehl’s picturefill script, it works very dynamically and seems very responsive.
All thoughts and comments greatly appreciated.