Yeah, you couldn't use that NS frame - BB would be lower like you said plus the head angle would be steeper. Like when people ask to put a sussy fork on a General Lee - just opposite.I see where you're headed, but wouldn't that make the BB super low with that frame? The geo on that NS is designed around a taller suspension fork, right?
On a side note, I'm still thinking about something in the 24" department. I've been riding the trails on my old 20" the past few weekends. It's fun, but feels soooo small and unstable compared to my 26. I'm thinking I'll build up a new 20 and 24, and throw them both into the rotation with the two-six. Is that too many DJ bikes?
24" rigs are great - I've been riding one since '85 when I started racing cruiser in addition to expert class. Something like the Tonic, USB or Nem is nice - still very flickable but the bigger wheels are a lot more stable than a 20" rig.