Yeah, I haven't messed with the Forge in H4 yet. I got really good with the Reach Forge, but this one's pretty different and I haven't had the multiple hours I need to devote to it to learn how to use it well.
But, you could make some switches using some of their techniques,I wouldn't recommend trying to create one of those monsters though... Pain in the ass and time consuming.
Probably 'impossible' or nearly so in H4 because we don't have the scale of a map like Forge World in Reach. Just 3 smaller Forge Worlds.
They call me Spoke Wrecker... Thizz iz what it iz GT-Spidux