I don't know if House Band has a way to filter the results, or if it always uses the full Media Center Library to do its searches. If it can't filter them, you should ask the developer to add that, as it seems like it would be a valuable addition (you're not the only person who would have this issue, certainly). If I was using it, I'd have that requirement as well. Preferably, you would have the ability to select a smartlist and use it to include or exclude items from the search results.
But, barring that, if you're willing to manipulate your filesystem locations for the files (or make duplicates), you could possibly do it like this:
1. Set up a special, separate folder on your media storage disk for the "highly rated" files that will be used on the Echo.
2. Load up the separate Echo Library, and set up an
Auto-Import Watched Folder pointing at only this folder. Make sure you have
Update for external changes enabled on that Library.
3. Load up your Main Library and make a
Smartlist that shows all of your Highly Rated tracks. You can make the smartlist even "smarter" by having it exclude any files that are already in the special Echo folder (use [Filename] does not contain "\my echo folder name\" as the rule). That way, in the future, you can always just use that smartlist to move files to the proper destination folder.
4. Select all of the files in that smartlist and use
Rename, Move, and Copy Files to either (depending on if you want to dedicate additional storage to the Echo versions): (1) move the files into the special Echo folder, or (2) copy them over to the Echo folder. If you copy them, it'll be nice because the originals can stay where they were untouched (and you can always just delete the whole Echo folder with no consequences). But, that will cost storage space, obviously.
5. You could even set up the Echo folder as a
Handheld in MC and largely automate the process (this will probably only work well if you are making copies, rather than moving the source files).
6. Then open up the Echo Library, and it'll auto-import everything in the special Echo folder. It should bring in most tags, as long as
MC is set to write them to the files (if any metadata is missing, you will need to turn on tag writing for that field).