Here is a shot of a WIP "scratch built" Arvus Lighter that has been sitting untouched on my "to do" shelf for over 2 years (the body has been in my blitz box for over 6!). Admittedly this isn't an exact match to the Forge World model. I am basing this project off Googled images and the body and cock pit used for the basis of the model.
The cockpit is a Lego Batman Happy Meal toy boat. The body is a Lego pre-Bionicle Technic robot container. The rest of the parts are miscellaneous bitz, plasticard and foamcore. I did purpose by the nacelles, landing gear (not shown), and other Valkyrie bitz for this project.
I have two more Lego boxes and Batman toys, with the intent to eventually make two more Lighters, but I will have to source more nacelles and landing gear--Assuming this project is a success!
Ideally, this vehicle will be put into immediate service of the Ordo Hereticus by our Dark Heresy acolytes. It's eventual and primary mission will be attached to my rag-tag Imperial Guard force.
If you are interested in reading more about my rag-tag IG force, check out these posts: