Several wrong answers below, but a couple are pretty close.
Shortest waiting period after a short sale with mortgage lates at the time of closing:
1.) 1 year USDA RDL Program (see link below for further information and comments below blog).
2.) 1 year FHA under the Back to Work Program even with a short sale on a FHA, VA or USDA loan with CAIVRS Waiver.
3.) 2 years VA loan (as soon as 1 year with extenuating circumstances i.e. death or serious illness).
4.) 2 years Fannie Mae with 20% down.
5.) 3 years Standard FHA 203b (you're considered a first time buyer again, no restrictions).
6.) 4 years Conventional 10% down
7.) and on and on....