http://en.wikipedia.org/wiki/Sherlock_holmesHmmm... the scholarship and performance angles are trickier. His knowledge is, indeed, based on what he finds necessary for his work and interests. Perhaps an investigative stunt along the lines of using investigation in place of scholarship for research on evidence would be the correct approach.
He certainly maintained a catalogue of knowledge of forensic investigation techniques.
How about 'Forensic Scientist' or 'Encyclopedia of Practical Forensics'
Additionally, Holmes was a master of disguise and able to mimic patterns of speech well beyond simply copying accents.
Victorian Gentleman would certainly be an appropriate aspect for Holmes. The aspect could easily be invoked similarly to Harry's own 'Chivalry is not Dead, Dammit.'
Dr. Watson describes Holmes as living a 'Bohemian' lifestyle (one characterized by few permanent ties and largely focused on the individual's own pursuits (frequently esoteric or artistic in nature)). This could also be applied to an aspect. Holmes does what he does not primarily as a career, but because it is of interest to him. He's not a man of the system.
He is a loner and prone to fits of fugue. In our day, he would probably have been regarded as a low grade manic depressive.
Order in Chaos Holmes personal space appears to any conventional person as an absolute shambles, but his organization is not based on convention. It's more organic and holistic. Things in his space are positioned based on relationship, and he knows right where everything is. Despite this, he is also fastidious about his own appearance and grooming.
Holmes is a patriot as well. In many stories he undertakes a case for the good of England.
Holmes is also a habitual user of cocaine and, on occasion, morphine.
Holmes is a talented fist fighter and also well versed in martial arts and weapons (he uses his cane and a sword in the stories).