The plugins your are talking about should work as well directly because the xFilterRow is using standard ExtJS form field. In fact that is what I like the most about this plugin, we could in theory use almost any component as filter header.
It depend, for my part I'm using the remote server side search, so to have an search with >4000 <5000 I personally do the code in my php or remote code execution.
Another way if you would like to do it locally would be to create a function inside the plugin that would make a filter on a field based on a filter function of the datastore.
Someone could help me with an example search with local or remote php (with operators to filter)? I know I'm asking for too much but I am newbie with extj..