Eric,
I'm not sure if you ever got a reply to this but the solution would be something like:
/MapServer/28/query?where=NAME+LIKE+%27%25OPEN%25%27+AND+ROWNUM+%3C%3D+3&f=html
Do you also know if there is a way to do something like ROWNUM via ArcObjects as this is essentially Oracle specific and wouldn't work for data in a File Geodatabase for example.
Thanks
Andy