North Island and South Island would be too good.
In all seriousness, maybe, though things will be skewed a bit because the North Island will have some insane depth (4 sides and most of the Black Caps to choose from) and the South Island would have just the two, and neither Otago or Canterbury are as strong as they once were.
Depending on when it was held, the top two teams from the HRV Cup would be the best idea, otherwise you're looking at a ridiculously stacked North Island side. To give an idea, Jamie How, who scored runs for fun in the CL, might not make the North Island side.
If you could get the teams to agree to teaming up, three NZ sides would do it. Auckland/ND, CD/Wellington, and the South Island would make for three strong teams with reasonable bench strength.
To give an idea (these teams are made up on the go and don't neccessarily represent who they would pick, nor do they include overseas players):
Auckz/ND: Watling, Guptill, Williamson, Styris, Marshall, Vettori, McGlashan, Adams, Mills, Southee, Arnel
CD/Welly: Ryder, How, Sinclair, Taylor, Oram, Franklin, van Wyk, Diamanti, Gillespie, Mason, McKay (Patel ****s off
).
South Island: McCullum, Redmond, Fulton, Broom, Stewart, Anderson, Young, McCullum, Butler, McSkimming, Wagner, Martin