Slaughter and May
Gibson Dunn
Skadden (although you also have to provide your extracurriculars and positions of responsibility as separate questions - but effectively a longer cover letter format)
Norton Rose Fulbright
Freshfields (personal statement, but effectively like a cover letter)
Travers Smith (although you also have to provide your extracurriculars and positions of responsibility as separate questions - but effectively a longer cover letter format)
White & Case (although you also have to provide your extracurriculars and positions of responsibility as separate questions, as well as details of events you have attended - but effectively a longer cover letter format)