I did an ESB for a clone competition in 12 days, mostly because of the deadline and not having good weather to brew until the last minute. It was a clone of a local brewpub beer which according to the brewer is crash cooled after 4 days of fermentation. I used Ringwood and open-fermented to match his process, although I waited until day 7 to cool and start carbonating. The result? No diacetyl and a great malty flavor. I let another 5 gallons continue to age at room temperature in a secondary for another week, and it finished lower than I wanted and lacked some of the richness that I got in the first version. I'd generally never ferment a beer in a week, let alone a 1.065 ESB, but this one really turned out nice.