I have one very similar to this, and love it !
http://www.sadoun.com/Sat/Products/Perfect/JVI_10-DSM1_Dual_Signal_Meter.htm
it is great for times when you want to aim two lnb;s at once, like torodials where you want to aim the outside lnb's at the same time.
it also tests 18/13v, 22khz, and current, this is a really handy feaure I use on starchoice setups all the time. I can attach my meter to the ird, tell the ird to goto right polarity or left polarity and the meter shows me with an led what voltage im on, and with the meter, the exact voltage that the ird is outputing.
I then test 22khz on and 22khz off, the meter shows me with the led what tone is there or not there.
I then attache the ird and the lnb and can test the current, this is nice for especially long runs of coax, or also if Im worried there may be a short in the coax.
what I like is the meter can be used in conjunction with an ird as described, or without an ird as it has its own battery pack. so you can aim a dish without the ird, get the dish setup, then add the ird into the mix later. this comes in real handy, as Im not allways the one installing the ird, just the dish sometimes.
its a little more then you were origonally looking at, but its something worth looking at.