Concert lens strategy

I'm getting more and more into indoor concert photography, and have had the pleasure of renting some pretty fine glass to accompany my 5D such as the 16-35L, 24-70L and 70-200 2.8IS. I have yet to use prime lenses for concerts but I understand they can be quite useful given their wide apetures.

My dilemma is cash I've conceded to the fact that my lens lineup will grow slowly. I currently only own the 24-105L, which gets me bye in well lit venues but has its obvious limitations being f/4.

So, the lens lineup paths I've considered for the immediate future are as follows:

Option 1)

• keep the 24-105L

• add two primes, from either the 50/1.4, 85/1.8 or 100/2.0

Option 2)

• keep the 24-105L

• add a Sigma 70-200/2.8 to help me on the long end

Option 3)

• trade the 24-105L for a 24-70L

• add a fast long prime, maybe the 135L or 200/2.8

Long term, I figure I will eventually settle into the 16-35, 24-70, 70-200 threesome plus a prime or two, but I need to stick to reality for now.

Any thoughts on what would be the most versatile option for the mid term?