Hmmm...depending on your definition of a playable state, I'd have to say the longest for getting one where I can get through it (randomly adjusting the tempo in some parts
) would be about 3 1/2 weeks to a month. I learned "Millionare's Hoedown", which is four pages long, for a Suzuki workshop down in Miami in October. It was only the most advanced kids (books 5-8) and I who played it. For an example of how fast they played it, take your metronome, and set it for about 208. Yeah; that whole thing about smiling when you make a mistake? Yeah. I grinned the whole song through. But, for the record?? I did memorize it, which took about a week.
Now, 'performable' you say? The "Bach Double Concerto" took me about 4 months to get memorized and performable. Listen to a recording of it, and you'll understand why.
To add onto it, what was your shortest time you've taken getting something playable??
P.S. Thank you for posting, martinezg!!