We have now completed our version of a Find/Find again routine that works with grid data. It allows us to search for any string in a specific column or alternatively in any character column of the grid.
The performance in our tests has been quite acceptable even though it uses the LOCATE and CONTINUE commands as the root search process.
The code to do this is incorporated in our own custom framework so publishing it in a clearly readable form is tricky but if anyone is specifically interested I can email the details.