Best from Xtar is probably still the Dragon VP4L Plus version which supports batteries up to 78mm long
I have & like the Xtar VC8 Plus for the 8 battery capability, and it charges 8 batteries at 1A each with the DC adapter.
I have the Xtar VP4SL I'm not real happy with it, but it does the job, and also supports batteries up to 78mm long.
I still like the Opus BT-3100 the best but it barely supports 71.8mm long cells. What I like most is that has 4 truly independent channels. Meaning; you can have 4 different batteries, doing 4 different things, at 4 different amperage settings...
I kind of want to pickup the SkyRC MC3000, it supports almost every common type of rechargeable cylinder battery - NiMH NiCd NiZn Lilo4.35 LiFePO4 LTO Li-lon RAM(?what is a ram battery?) - that will fit in it... but not sure what battery length it will handle. It is however on the expensive side.