Actually i do try and use the search engine before i post, it can sometimes eliminate ignorant posts i make mistakenly make. Theres already multiple kinds of games for this series which stops the question on what you would like, since most are already out.

How would it be fact that Gai would stand any chance towards him? It hasn't been done before? We dont exactly know what Gai's/Itachi's special ablities may be? For all we know Itachi may be centered around having a advantage towards taijustu which we can presume is Gai's main focus. Kakashi is on par with Gai, fact, Kakashi lost against Itachi, but stood somewhat of a little chance, fact, but is Gai Kakashi? no, there are way too many factors that could total change the way the fight goes, because we know very little of both of these characters.

For all we know Gai could be Massacred in a few seconds. But its likely that he will stand a chance, thus debatable.

Edit: dammit i did it again, sorry.

ReEdit: ?igma i dont know what i did to provoke you, but the avatar is the dog from FMA, as i notice yours is from Hellsing.