I was able to get my hands on a set of these recently from Federation Models:
And just earlier this afternoon took them to Staples to get enlarged so I'll have a 1:1 template for scratch-building my own studio-scale Runabout model.
The build will consist of styrene and Sintra (PVC) board, with a few small components (smoked acrylic for the portholes, clear ribbed acrylic for the nacelle vents) done by the shop near me.
I even intend to fabricate the add-on mission pod, but will have it magnetically attached if I decide to display it without. I do plan on lighting it, though I'll probably need some help with that.
Once completed, this will measure 19.5 inches long (based on information noted in my "Star Trek Prop Paint Codes & Dims" Word document).
I hope to be able to really get into this project once I've got the few commissioned builds I have outstanding done as well as a few other projects.