Hi,
I guess it depends on how you define 'lead' bass, but if you mean bassists who play melodies and front their own bands, there are loads. For starters try Michael Manring, Abe Laboriel, Billy Sheehan, Stu Hamm, Victor Wooten, Steve Bailey, TM Stevens, Adam Nitti, Jonas Hellborg, Jimmy Haslip, John Patitucci... there are loads. Check
http://www.solobassnetwork.org.uk for guys who play on their own - some of them also sometimes use bands...
cheers
Steve
http://www.steve-lawson.co.uk