The problem with multi-battery chargers is that they divide the current by the number of batteries being charge, so 2 batteries will take twice as long as 1 battery, or 5 batteries 5x as long. Kind of defeats the purpose...
Only way around that would be to have each battery separately regulated, which is basically 5 chargers stuck together at the 5x the cost, or have some electronics that sense how many batteries are being charged so its isn't sending 5x the power needed to one battery making it a mini rocket launcher. Again 5X the cost.
Honestly if you want to charge X number of batteries at the same time, buy X number of chargers. Its going to be the cheapest, most effective and versitile way you can do it.
You could consider buying more full kits.. You are going to need all the parts in the kit sooner or later anyhow. Considering the spare parts you get in the kit purchased separately, you would be getting another charger for next to nothing.
I'm a bit lost to the point anyhow, with an eGO it takes about 2 hours to charge. If you are able to discharge the one you are using in under 2 hours before the other one is charged, you are doing something rather wacky with it

Stop powering the patio lanterns with it