Has anyone framed a balloon wall with floor trusses? If so, what did you use for a ledger? If the floor truss is 2' tall I would guess you can use a 2 x 6 for the ledger and allow the top to have a 2X gap to the wall as the decking will extend to the outside edge of the panel. Or if ballooning the SIP for two floors, you might want a nailer on top to attach the deck to the wall??

Most manufacturers have a detail for "balloon" framing. Typically it is not exactly the same as what is conventionally considered balloon framing, but the end result is the same. Check out one such detail at http://www.insulspan.com/professionals/specs/assembly - Floor to Wall Connection Type 1