LimeWire used an auto-search for hosts it had either been downloading from or recorded from the search results. It does this every half an hour or so. But this is not a repeat search function per se.

Unless I'm mistaken, MP3Rocket which is a LimeWire4 clone had a rating system. Not used as you propose though. It also had an option to download from youtube with a dedicated window for this purpose.

Bitrates, something I've been requesting for ages for Phex.

I would like to see a file-description tool for Phex to help advertise its shares. Worked very effectively in LimeWire (v.4's was better.)

Definitely like to see the Phex developer population grow.