Artwork or utilitarian, same drill, chassis are kind of too specific to a build to be able to be in a program like MHS Saber Builder.
I designed a few "standard" sized chassis for most soundboards, but in the end I always create new design for the particular hilt I build :)
So best advise for now, start gathering info about everything you need to fit in your hilt (board, battery, ports...), and then see the dimensions of where you wanna put that (ID and length of the hilt).
You can sketch that on paper for example and see if you can find something among the existing designs out there that would work for you, or ask someone to design something specific for your hilt.