I tried searching and I don't think anyone has posted about this yet. Hanson has been hosting a music writing session called "The Fools Banquet" each year in February for the past few years. This past year, Stephen Kellogg attended and during the tour, Taylor came out on stage and performed a song called "Song for Jim" with the Sixers. There's a couple videos on youtube, my friend took this one:
http://youtube.com/watch?v=vVpClR5YCDU
They also wrote a song called "Coming Back for More" with SK that Hanson released on a special kit for their Fan Club members. The studio version has just Taylor singing but they performed it live twice with Stephen Kellogg on stage.
Here's someone else's video of one of those performances:
http://youtube.com/watch?v=TKcMK7NOSec
