Wikipedia
Kellan
Kellen is German in origin and Irish in spirit. Kellen is in the Top 500 and has possibilities for girls too. In fact, Kellen's similarity to such feminine names as Helen, Ellen, and Kelly might make it a tough one for a little boy to carry, though the macho image of Twilight actor Kellan Lutz will help with that. or "powerful".
or "bright-headed".
Other variations of Kellen or Kellan includes Kaelan, Kallen, Keelan, Keilan, Keillan, Kelan, Kelden, Kelle, Kellyn, and Kellin.