I think what Mosaic 2.0 does with <ISINDEX> is reasonable, but it
does force a tough choice on the document provider who must either:
1) Obey the DTD and put <ISINDEX> in the <HEAD> and live with the
search field being right at the top of the document.
2) Make the document non-compliant to the DTD and put <ISINDEX>
where you wish to see the input field in Mosaic 2.0.
If you're a bit fast and loose (like me), the choice is easy. You
can do (2) and know that the Mosaic 2.0 user will get a better
than average interface and all the other current browsers still
recognize the misplaced <ISINDEX> tag OK so no problem.
But if you want DTD conforming documents (and you're justified since
it's your only guarantee that future browsers will interoperate),
Mosaic 2.0 users see things a little weird.
So how about this: If <ISINDEX> is in the <HEAD>, Mosaic puts the
input field at the end of the document. Otherwise, it puts the
input field wherever <ISINDEX> appears. As long as your search
pages are short, this will give you very similar behaviour to
Mosaic 1.2. And maybe it's not that hard to implement (but if
it is, don't bother).