Phasescope in protools does Leq(A) and this: (free - Windows only)
ORBAN Loudness Meter
does the ITU.BS.1770 (Leq (RLB2))
Mult a fixed-level digital out from your mixer to a laptop running whatever's necessary and measure away with pretty good confidence. Remember that summed mono on a LM100 will be +3db when looking at these stereo meters.
Other options for the BS.1770 include using the 14 day trial of TC LM5D (PT HD)
TC Electronic | LM5D
Those are all the "free" ones I can think of.