kjjack, check 240.6; 240.20(B) and the exhibits 240.4 through 240.6 listed in the 2009 NEC. It seems that your proposed solution is permitted but isn't commonly applied in that fashion. The most common application is to use individual single pole C/B'S as was mentioned by "jghrist". Further...
I'm in the market to purchase a new meter to measure KVA, KVAR. I'm looking at the Hioki 3286-20 or the Extech 38096. Both are three phase clamp on meters and I'd like any feedback from anyone who's used any/either of these two meters. The next one on my list would be the Fluke 1735.