I found this song (not the best quality) but nonetheless, kind of a cool collaboration between Brooke White and Michael Johns. Brooke White's fan site says she will have an album debut in June?
I loved when she sang You're So Vain on AI, and here is another version she sang very recently.
I was also a fan of Jason Castro (maybe I was the only one?) and found this performance he did where he covered Crazy by Ray LaMontagne (the video is horrible, but the sound quality is pretty great, so just listen w/o watching). Apparently from info on his website and facebook page he is performing all over the country but hasn't released any album yet.
Last season was the first AI I had watched since Clay Aiken lost (well, okay, I watched the Fantasia season but wasn't ever that impressed) and what got me watching again was the variety of talent and the indy rock feel of many of the top 12, in addition to the musical instruments they played during the performances.
I just hope the show delivers with variety again this season and finds a few who can also play guitar or piano.