Hi,

The attached patch implements in-buffer coloring and html export using
the syntax proposed below.

While I think this is an improvement over my previous patch, this idea
still has some shortcoming including the fact that
- nested color specifications aren't working for export (and could be
  tricky to implement)
- when using a dark-background Emacs theme colors that look good in the
  buffer generally don't look good in the html export and vise versa

The following Org-mode buffer demonstrates this patch
--8<---------------cut here---------------start------------->8---
#+Title: A Buffer with Color

* top
Some colors [color[green]are] green, and [color[red]also] red, and even html colors
like [color[#610B5E]these others] sometimes subtler colors.

These can also be [background[yellow]highlighted].
--8<---------------cut here---------------end--------------->8---

Cheers -- Eric