I don't think you are going to find a decent 4 channel charger that supports USB input as it is just too much current for a typical micro USB cable they tend to not take much more than about 2-3A. I have a single channel charger that takes micro USB.
The Opus BT -C3100 is about $40 online I don't have one as my budget ran out before I could get one I am using an Opus BT-C100.
I think you need to decide a few things before you invest in a charger: What type/size cells you want to charger, if you desire to analyze (charge/discharge testing) cells or not, current settings per chemistry (lowest, highest current), readout (analog, digital) and power source.
If it were me I would lean towards a charger with a 12v input so you could in an outage plug it into a car and use the car battery to charge off of. Some 1-2 channel chargers have micro USB inputs so you could use a USB car charger with them perhaps.
Unless you are using a light putting out massive amounts of light you may possibly get by with a 1-2 cell charger instead of 4 channel but
most 4 channel chargers that do lithium ion also do nimh too.
You could also try looking at HKJ's site for reviews of chargers to give you some ideas.