I am sure it could.
What do you want out of the arduino that the commercial controllers do not provide?
Myself, I would need a strong reason to give up the safety and reliability of a commercial unit.
If you want just the motor, here is a page of 24v motors (that would run well on a 6S LiPo)
http://www.monsterscooterparts.com/trsc/rec-categories/motors1/24voltmotors