Sherlock Holmes Consulting Detective is a very good game, but it completely lacks of replay value. Sadly, there is no way to replay a case when you have already solved it.
The only option left is to act as a host, and try to enjoy a session where other people try to crack the case. But being a host in a game where you would only read aloud some pieces of text is not very appealing. So, why not add some spice to it?
I've written some guidelines to transform the game into a roleplaying one, so whenever you solve a case, you can replay it with your friends as a host and have an active role.
I've chose Gurps Ultra Lite for the ruleset because it's extremely simple and it's free. Follow that link and download, print, fold and read it. In that order. You will understand when you see the pdf.
As I've said, it is simple. The whole thing fits in one single page. I chose it because I don't want to steal attention from the main feature of the game, the deduction process. When you have read it, read my guidelines and print the character sheets, and you'll be ready to replay the cases.
You can find the guidelines and the character sheets in the BoardGameGeek site.