So far you still can use a seblod form for the generic search.
We developped a text field plugin which is ajax powered so that when you start writting in the field you get the automatic suggestions from the title, introtext and fulltext of any content. This is the Autocomplete field plugin we are now using in our projects.
We may put it for download when the market is open for third party contributor.
Instead of putting the CCK field in the RESEARCH tab of the form (because you don't want to search on only one content type, we then just put the autocomplete field and... voila!
This new generic search produces right rewritten sef url when the smart search (com_finder) only produces wrong ones unless you add hidden menu items.
Our first version works (we use it on several projects) but is not easy to install since we must:
install an ajax component to deal with ajax calls
install the autocomplete field
copy/paste a special view for the ajax component to make the link between the autocomplete field and the ajax component
So far the autocomplete field displays the same database field as the one it stores (TEXT = VALUE). We are working on a new version that can display a field from the database(example the TITLE) but stores another fields (example the ID) and proposes extra fields as attr1, attr2 etc...
As soon as this new autocomplete field is done we will publish it