probably should be able to base a flame wall build off any old scorching ray more or less.
necro, elem, or templar.
elefocus, spiritural aid, divine judgement.
orb of storms to proc EE likely. with added cold damage to spells gear. dont make use of added fire damage to projectiles yourself. I would think EE would be more damage, then using spellslinger and power siphon/barrage, whatever.
probably not use spell cascade. let you cast walls in different locations, instead of 3 in one spot.
Can get real fancy with burning arrow, and ignite. just remember Burning is not ignite. Burning is not an ailment. Elementalist bacon of ruin for example, does NOT effect burning.
go herald of ash/golems if you go elementalist.
which actually, yeah. elementalist EE.. discord and elemancer.
herald of lit, ash, and ice. Ash does not ADD fire damage to spells. it "gains phys as fire". so orb of storms will deal ice and lit damage. While Ash will buff your burning damage greatly.
A triherald orb of storms ought to autobomb most trash as well.
super basic start. self cast. not even getting into uniques, or any thing.