What would already work for me is the ability to copy and paste soundcloud page links and Roon would extract the audio feed. That would already meet the need, it is not a major inconvenience to tab back and forth between google chrome and the roon app and do the paste. At least this way I can listen.
A very simple and basic search will do fine. On soundcloud results are grouped in Everything/Track/People/Playlists/Groups, but even that is overkill I think, just the ‘Everything’ search result would do fine. As you say there is not really a metadata structure within soundcloud, so the search there works a bit like google does where it scans the uploader and stream name mainly.
A huge thanks if you could make this happen. My 2 week trial just ended and I can’t imagine ever going back, absolutely loving Roon.