it is interesting that you should post this today john.
i am involved in a new print exchange over on hybrid with the guide line being no smaller than 11x14 no bigger than 16x20.
am finding that i am not happy with any images that i have been testing at this size, perhaps because i have been doing so much alternative work the past few years along with polariod manipulation that it is hard to shift gears.
i agree with alex, large is a bit over done these days. i am a firm believer that the image dictates size and have rarely printed large in any medium.