I decided to try play around with your tower a bit, shamanyouranus.
This is what I managed to achieve using the "element_sprite" attachment point. The results are somewhat promising.
In the picture:
Abilities\Weapons\DemonHunterMissile\DemonHunterMissile.mdl
Abilities\Weapons\ChimaeraAcidMissile\ChimaeraAcidMissile.md
Abilities\Spells\Other\SoulBurn\SoulBurnbuff.mdll
Abilities\Weapons\BallsOfFireMissile\BallsOfFireMissile.mdl
Also suggest:
Abilities\Weapons\BansheeMissile\BansheeMissile.mdl
Abilities\Weapons\AncientProtectorMissile\AncientProtectorMissile.mdl
Abilities\Spells\Other\Volcano\VolcanoMissile.mdl
Abilities\Spells\Undead\Possession\PossessionTarget.mdl
Abilities\Spells\Other\Parasite\ParasiteTarget.mdl
Abilities\Spells\Other\Parasite\ParasiteMissile.mdl
Abilities\Spells\Human\ManaFlare\ManaFlareBase.mdl
abilities\weapons\catapult\catapultmissile.mdl
Objects\InventoryItems\CrystalShard\CrystalShard.mdl
Abilities\Weapons\WitchDoctorMissile\WitchDoctorMissile.mdl
Abilities\Spells\Items\OrbCorruption\OrbCorruptionSpecialArt.mdl
Abilities\Spells\Undead\Cripple\CrippleTarget.mdl
Abilities\Spells\Items\PotionOfOmniscience\CrystalBallCaster.mdl
Abilities\Spells\NightElf\Barkskin\BarkSkinTarget.mdl