disabled attribute in option tags

There's currently no way to set the disabled attribute in options generated by the form helpers.

I've created a patch that allows you to specify which values should be disabled in your options:

http://rails.lighthouseapp.com/projects/8994/tickets/837-patch-specify-the-disabled-attribute-for-option-tags

Any comments?

OK, I thought that this patch would have no side effects but I've just
realised that some people may be passing selected elements without
array brackets. This means that options_for_select(container, selected
= nil, disabled = []) will interpret the first as selected and any
subsequent ones as disabled. Does anyone have any suggestions?

Also, is there any reason why the disabled attribute is not supported
currently?