How can HD skins be used as Minecraft avatar in SMP?

The 64x32 pixels of the default resolution skin look rather poor if one uses an HD texture pack, but that's the only resolution allowed to for upload to the profile on minecraft.net. I can of course play in offline mode, which gives me the texture pack's default char.png, which I could replace with my favourite HD skin, but in SMP everyone would look the same (if the server doesn't require online at first, that is).

Is there any possibility (vanilla, client mod, Bukkit plug-in, etc.) to walk around with HD skins in an HD world?

There's a mod that allows for HD skins, ear skins, and capes via a third-party site. They will even show up for other players using the same mod on a multiplayer server.

The possibility does not exist yet, but then again, why would you wanna do that? The whole game is about squares and pixels. This would ruin the experience of Minecraft.

I also remember something about Notch saying he wouldn't want that, because then people would bring 18+ stuff into the game via their character skins.