http://www.csse.monash.edu.au/~jwb/wwwjdic.html

You can get a list of characters searched by romaji here:

http://www.csse.monash.edu.au/~jwb/cgi-bin/wwwjdic.cgi?1B

Using that second page, you can search on mi, ge (or gei, if you like) and ru to come up with various combinations.

However, once you just choose a combination, if possible, get someone with native Japanese or Chinese language ability (that would not be me) to check the passability of your desired kanji combination.  Sometimes people (including myself) come up with really ridiculous-sounding/meaning character combinations (see http://www.hanzismatter.com/ and http://www.engrish.com/ to see what it looks like with the shoe on the other foot).  Actually, what passes in Chinese may not pass in Japanese, and vice-versa (although, three characters in Japanese are quite rare anyway.)  And remember, as your name will not sound the same in Chinese as in Japanese, you would only ask a Chinese for a sanity check based on the combination and order of the character meanings.

Truth unfolds in time through a communal process.