Okay, not very original, but still. My problem is that I'm just not a very creative person, so coming up with some cool original designs can be a real struggle for me. Here are a few creative-ish designs that are now up on my Cults3D store.
The Imperious PTERYGA Interceptor
Inspired by the many experimental flying-wing designs of the 1940's and 50's, the Pteryga (which is cleverly the Greek word for "wing") is a long-range interceptor with a super low front profile. The pilot actually lays prone instead of sitting up.
The GothiTech Armored Train
Come on, armored trains are a cool throwback to the last century. This one is heavily Gothicized to match the Epic 40K aesthetic.