You actually really want 3D Modeling software, doing this in photoshop and keeping allthings equal will be a bear.. photoshop just isn't designed for 3D.
Something like Ulead 3D is very simple, and maybe not exactly what you're after.. but it's the cheapest of the ones I can think of.
The thing is, with photoshop, you will literally be manually drawing this thing from different views, which will make keeping scale and ration exceptionally difficult.
But, it's all up to you
