so, it turns out that even though isindex is depracated in favor of using inputs, there’s really no elegant way to do what isindex does with inputs – that is append a value (not a name-value pair) to the query string. (neither moz or ie will submit a value without a name/id) so, the way i had to do it is by way of silly javascript hack (calling a document.location change onsubmit of the form).
My Sidebar Developer’s Guide – this does not have any information on how, if it is possible, to make a particular sidebar tab pop up/out. oh, never mind just learned that it’s bug 14224.