Ive modified Jean-Lucs awesome https://bitcointalk.org/index.php?topic=345619.msg3759147#msg3759147 vanity generator. His original one searches for patterns. Mine lets you search for very short account numbers (accounts with lots of leading zeros). I have a .zip file of the .java source and the compiled .jar attached to this post. While I can assure you this will not send any passphrases to any remote server, I cant assure you this will not set your computer on fire (Im just pretending to be a programmer here). So far I've been able to generate an account with as few as 7 digits!
Usage: java -jar Vanitylen.jar [MAX_ACCT#_LENGTH] [SECRET_PREFIX]
if only 1 option is specified it is assumed to be [MAX_ACCT#_LENGTH] and a prefix will be generated for you
For a given user-supplied secret prefix, the sequence of generated account numbers is always the same. This is in order to keep the number of characters appended to the secret prefix small. So it is extremely important that you pick up a strong secret prefix. Anybody who can guess your secret prefix can just run this program with it to arrive at your full secret phrase. This obviously doesn't apply when you let the program generate the secret phrase randomly (i.e., running it 1 parameter).
The sha256 hash for my .zip file is 250ba45db957575d93d239aab523eae82e9001efdc8953b98452a96fa55e7957 http://forkedchain.nxtcrypto.org/vanitylen.zip