You can bet that if Google announced it wanted some editors to work on a new Google Directory that you would have 100,000 applications sent within the first 10 seconds even if they weren't willing to compensate you financially.
'Years'? It would take only a few months to get up to Dmoz's level.
I feel that Google would benefit from making it's own directory. Looksmart was one the most corrupt and easily fooled directories I'd ever come across. Dmoz is getting that way aswell, I can't even count the number of bribes I was offered to pass duplicate inclusions or to put keywords in the linking text rather than the company name.