I also had a look at creating a temp table. Wasn't sure what was happening with temp tables, as I couldn't get it to stick in phpMyAdmin.
But I did get as far as getting it to create a table, and insert the 'ckbox' string into it, using:
mysql_query("CREATE TABLE profilesTemp (profileIDS VARCHAR(100))");
$profilevalues = $_GET['ckbox'];
mysql_query("INSERT INTO profilesTemp VALUES('$profilevalues', '$project');");
But no idea how to then tie that back to the appropriate results in the revision table.
I appreciate that this is getting a bit removed from the WA functionality, but if this was something you might be able to help with I'd be happy to pay for some paid support with this one, as I think it would end up with an incredibly robust and flexible search function.
The other thing is I have a version of the search page that uses the checkboxes only and does return exact matches. So I'll have a go at recreating that for this project and then have a look at seeing if its possible to add the WA search part for any text fields.
This is the trouble I always find - so many ways of doing things, just getting the one that does everything at the same time!