C99 & A11 aren't exactly new, but both finish between 45 & 55 days and unlike most fast strains, actually get you HIGH which SHOULD be what every grower is aiming for instead of all keeping getting high a non option & continuing the lemmings march for indicas. C99 and/or A11 (i actually used C99 x A11 as my last male) will always be a cornerstone of my breeding and in my garden at least in cross form unless someone comes up with a 3 foot tall autoflowering cambodian or something better.
at the stonier end of the spectrum, high quality seeds' masterkush takes 60 days, but i bet it yields like a mofo in sea of green if you back cross it to get enough plants to fill a room. it's gotta be an auto as it flipped itself under 24h in about 3 weeks from seed. it's super compact & dense and the buzz is nice for someone like me who despises couchlock. it has some stone going on, but not the narcotic sleeping pill variety, it's pretty much what i'd call a mid and not that different from skunk #1. i bet if i didn't switch it to 12/12 and gave it at least 18h a day, it would have yielded even better. i really liked the look of one "red pheno" gal that is my breeder for a mid.
i imagine the fastest plant would be some lowryder that benefits from faster switches to flowering. i'd try a C99 auto if someone made one.