While setting my PS3 up for Divx video-on-demand I noticed that the only current UK-licensed provider - channelfilms.com - actually has a bunch of stuff that would interest this board. They've signed deals with Arrow, Salvation and a bunch of other small DVD companies to provide their titles so there are bunch of euro-horror, foreign and cult titles available. The prices are fairly good too at £1.99 - £2.99 for rental and £3.99-£6.99 for own. You have to download the titles to your PC (dunno if works with Mac) and then you can copy them to any Divx-certified device (incl. PS3, DVD player with ethernet connection and Divx, Divx-enabled mobile, etc.)
It's not perfect but for VOD of the more obscure stuff it's a start.