Something like that?
select :disabled.red { color: red; }
Here's a document on :disabled pseudo-class from Microsoft.
Here's a fiddle that should work in IE9 and above .
Update: This only seems to work in IE> 8. This answer points to a workaround for using the readonly attribute on form elements. This is not an option for an option tag.
There are JavaScript workarounds for older IEs. A simple google search led me to this site that provides a jQuery solution.
From the blog post :
Adding a bit of stylistic css magic, you get the same result in all other modern browsers.
Then you can enable or disable javascript usage. Many people have written code that makes an option look like it's disabled, waiting for a click on an option item, and then blurring it or focusing on the next / previously selected option to make it act as disabled.
I came up with the functions used with jQuery, to disable / enable select an option, transferring it to the optgroup and vice versa. It is tested in firefox 2 and 3, safari 3, i.e. 6 + 7, and works in Opera 9 (although opgroups jump to the bottom)
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