Hi Andy,
Depends on several factors but primarily space, heat, light and nutrition. If all variables are optimal you can go from cross pollination to seed harvest in a few weeks. Then seed to new blooming plant in a matter of 4 to 6 weeks. Typically, if you do it the way Louis and I do with starting seed indoors under artificial light, you would be looking at 6 to 9 months.
I get about one cross and one new plant per season. The process is slow and frustrating because you do not usually get anything spectacular. Most of my crosses to date in the last 7 years have been mediocre at best.
Luck has the most to do with new discoveries as does the ability to grow out many seedlings at a time.
Cheers,
Sean