the 30 ms "ping limit" is acutally an authentication mechenisim.
during this 30 ms, there is a key exchange made between the client and host.
the key that is passed is the D-H key (Dille-helfman i believe its spelt), which is a verylight weight encryption, if im not mistaken, the key is stored on the disc and is called "LAN KEY". which is used to decrypted the D-H encyption.
so in that 30 ms your 360 needs to encrypt the KEY, exchange the key and Decrypt the key.
the only viable method i see of KAI/XBC being able to "bypass" this ping limit, is to have the computer (gateway) pre encrypt the key (to save a few Ms), and thats about all they could do, if thats even possible.
if that is the case, than:
XBC/KAI would need to have the D-H encypt algorithm (prolly not that hard to find).
The LAn KEY from the disc (not sure if this is diffrent for every copy of a game, but prolly isn't)
and the console id (thats the part being encrypted if im not mistaken).
sounds like fun for a programmer.... not.