Flea has signed & Fleabass and it’s currently for auction on eBay:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160394855503#ht_500wt_1182
All proceeds go to The Silverlake Conservatory of Music:
The mission of the Silverlake Conservatory of Music, a non-profit organization, is to facilitate basic music education. Our primary focus is on the youth of the community but all are welcome and encouraged to participate. The Conservatory offers private music lessons at a reasonable cost and grants scholarships to children in need, providing free lessons and instruments. The study of music enriches the life of the student as well as the community and society.