By selling the FZ10 away, you can hardly buy any lens. Left aside SB800, you will still need to top up $$, and at the same time, finding yourself handicap while you are on holidays, really not worth it.
I went to SBG today, and saw 1 lady was happily using the FZ10. Had a chat with her, and realized that she is also looking for upgrade. She also has a friend who told her that she will certainly need to keep more than 1 cam when she upgrade.
You can harddly find a cam that is as good as FZ10 nowadays. even the FZ20 is no match with FZ10 in terms of photo quality.