you can do it. www.warmoth.com sells 22 and 24 fret conversion necks. the thing is, you may have to take your neck pickup out to fit a 24 fretter in.
and the biggest thing is, will you actually be able to reack the 24th fret? if your guitar currently has 22, then the cutaway was probably designed so you could just reach 22. if you add 2 more frets on, you won't be able to reach any farther.
perfect example of this, gibson les paul doublecut (studio?). i tried one in a guitar shop. sure it has 24 frets, but what's the point when you can only reach 21?