Accessibility UAWG: contrast control

Chris and members of the UAWG,

it has been asserted by a number of people that a contrast control for 
an SVG user agent is 'trivial' to implement*.

UA and AT guidelines would without doubt encourage adoption of this and 
other accessibility solutions.
Please could a draft be published?

regards

Jonathan Chetwynd
http://www.peepo.co.uk     "It's easy to use"
irc://freenode/accessibility

* 37 minute exchange: 
http://svg.jibbering.com/svg/2004-11-15.html#T15-45-41