I know this isn't the response you're looking for, but it might be of some help to you - or others with a similar problem. The game allows the use of accented letters (usually vowels) for names. These accents aren't overly noticeable in actual play, and could be better than a "variation" of the desired name.
For your name, Knighthawk, both the i or a could be accented. The basic form is to press control&alt&[insert desired letter], but if you know how to get other accents (or a website you can copy and paste from) there are more options. You could easily get Kníghthawk or Knightháwk (assuming they haven't been taken). Using this trick with the letter "i" is especially potent, as it is almost indistinguishable.
Mind you, accented character names are a pain to invite to guilds/parties/ops.