to zreynoldsp: its a very general number (1,000) and many people have loosely used it as a benchmark goal, the point is that it is just a number and is not the "final" or only determining factor obviously, many things go into being a virtuoso as you imply.. however mastering "everything" on the instrument is not one of them.. For example virtuoso shredders do not necessarily need to master fingerpicking techniques to be a virtuoso (or vice versa) the point is that yes there are more than just a number on a metronome that are involved, but those things are not the same for every player or every style...
When people ask something like, "how fast do I need to play scales or arpeggios (for example) to be at a virtuoso level?" the 1,000 number is the one usually given as a benchmark. It is not set in stone of course and it also does not imply that if one plays scales and arpeggios at 1,000 that he/she is considered a virtuoso automatically. In general the labels are not important though, but for many people, they want to know what others think this benchmark might be...
Tom Hess