This is obvious to me. Is anybody doing work on it?

When I started getting into web accessibility it immediately occurred to me how useful it would be for there to be some standard strings that could be inserted in the user-agent-string so for example instead of 

Mozilla/4.04 (Win95; I)

you would have 

Mozilla/4.04 (Win95; I; ; IMP-CONT IMP-AUD)

and the person building the web application could easily code in quick work arounds for any tricky accessibilty cases.  A quick brainstorm suggests

IMP-CONT - the user requests high contrast output
IMP-COLx - the user is colourblind (x denotes the type of impairment)
IMP-AUD - the user cannot reliably use auditory senses so please use visual
IMP-VIS - the user is not able to perceive visual output

Is anybody doing work in this direction?

Regards,

Steve.