I'm working on Scion trapper. Arc Traps for farming, Lightning Spire Trap for single target.
This is the build I'm using: https://www.pathofexile.com/forum/view-thread/2151195
Path of Building: https://pastebin.com/s9MXapDa
I thought about Scion, cause it should basically work the same after taking Path of Shadow node, later just respec points used to get to Shadow area. Then we have easy access to Scion's life wheel which allows to modify base tree a bit and do not take hybrid Life/ES nodes, but only Life nodes instead.
Now, what do you think about Elementalist as second class? Maybe something from Templar would be better? Build I linked to uses DW wands, but since I want to play with 2 main spells I thought staff would be good idea, since 2x 6-link, each for one main spell. What staff do you think would be the best for that? 4-link Arc Trap for farming seems to be too weak, since 2 gems (Trap Support and Cluster Traps) are only modifiers to skill mechanics, not giving any real damage.
Sorry I can't provide current tree I'm working on, I'm not at home until tomorrow evening, but given all above, that should be good start to some brainstorming.