Forge World is your dream.
If you're looking for Elysian Chimera based, *shudder* try having a look at combining a Tauros (or 2, or a Venator) with a Chimera. Make them on wheels.
Perhaps a Predator Turret (Baal Flamer for Heavy Flamer/Inferno Cannon, swapping autocannon for a single Lascannon = multilaser, and there's no point in a heavy bolter).
Lemon Russ, could use the Mars Alpha hull - more sleek.
As said, taking any spare standard lasgun muzzle breaks, clipping them off, and the Bullpup carry handles, and reattaching as scopes are the way to roll.
Could perhaps look into current attachments on weapons - telescopic stocks, longer barrelled DMR rifles, bipods, foregrips, UGL's, MASS, railsets, perhaps changing the ammunition box from a battery to proper ammuniton, etc.
Have a search round tactical websites such as UKTactical for ideas.
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