Forgeworld 40K Warhound Titan is 10.5" tall (says so on website). Their Epic Warhound is 1.5" tall. GW Warlord= 2.75" tall.
2.75/1.5= 18.3333333333333333
3333333333333 X Forgeworld 40k Warhound 10.5"= 19.25" Warlord Titan. This equation also has the 2" tall Epic Reaver coming out to 14" tall in 40K. They just released it and it's 14" tall!
This will be our measure.
The little Defense Laser is .5" long, The Warlord's Volcano Cannon is 1.5" long or the height of the Epic Warhound, so that little gun will be 10.5" in 40K. I guess this is doable in 40K.
Anyone doubting the Defense Laser bit just has to compare it to the MK I Warlord Titan's Defense Laser, they are identical weapons with the Imperator's in a Basilisk type turret mount. It is also listed as a Defense Laser in the Imperator's profile.