I think the last time this was discussed, someone tried to make a converter that would connect directly to Lisa in order to avoid digital-analog-digital conversions.
HDMI only says what the maximum resolutions are, not minimum. and there are some adapters that have 640x480.
anyway it should be easy for someone with PC and HDMI to test and see if 320x256 works.
I think the problem would be finding displays that support these resolution. TV's with HDMI I've seen won't actually accept 480i/576i over HDMI (they'll take 480p/576p just fine though).
Even stranger, some resolutions are only available in certain 'modes', even though they use the very same plug and connector... Take my TV for example: it will happily display 1280x720 and 1024x768 (as well as higher and lower resolutions). However... If the input of the TV is set to HD it won't display 1024x768 and if it's set to PC it won't display 1280x720.
One wonders why they went to the bother of blocking some resolutions in some modes, even though the TV itself can actually display it (like the 576i thing - works fine over scart and component, but won't display over HDMI at all - even though the signal is there and the TV can display it!). It's almost as if the designers are going out of their way to cause frustration and trouble for those who wish something not-everyday.
I suppose there will be displays that do work with resolutions below 480p, but your milage may vary.
