It's rare and wonderful to find a fansub group that's interested in classics. I can think of many suggestions, but my top priority would be the first of Osamu Tezuka's Animerama movies, 1001 Nights (Senya Ichiya Monogatari) from 1969. AniDB IMDB
I've had no luck finding a group interested in subbing this, even though it was a Tezuka production and one of the major landmarks of anime history. Some might call it the first hentai, but it wouldn't be considered hentai by today's standards. It contains about the same level of sex and violence as a typical live action Japanese film from that time. But it is groundbreaking for being one of the first examples of anime to cater exclusively to an adult audience.
I can provide the raw DVD. If you want to preview the film, it looks like someone has already uploaded the whole thing to youtube here: http://www.youtube.com/view_play_list?p=2AE21A0D1A19856D
And if you like this, I would also like to suggest the second film in Tezuka's trilogy, Cleopatra, which I could also provide as a raw: http://anidb.net/perl-bin/animedb.pl?show=anime&aid=4579
The last film in the series, Belladonna of Sadness, has already been subbed by myself based on existing Chinese subs and a little help. They're mostly okay but could use improvements. You can find MWizard's encode of that one right here