Reference on the K-7 Space Station is hard to come by. Only grainy prints from The Trouble With Tribbles seem to survive. More recently, Greg Jein has rebuilt a model of the station for the DS9 episode Trials and Tribble-ations. Photos of the Greg's model can be found at the IDIC page (see links below).

Phil Broad has found this image (Click to enlarge), posted at this page. The picture is of an inflatable Douglas Aircraft space base - the influence on the design of the K-7 is obvious!

Until recently, fan publications have depicted the K-7 as being ribbed, like the AMT model. Greg Jein however, interpreted the model according to the Douglas Aircraft proposal. Once again, I'm siding with Greg's interpretation. I diverge from his on one detail, however. Greg built the K-7 with eight sections per pod, but the Douglas station has twelve. I've poured over every reference photo I have, and I feel strongly that the original K-7 model had 12 panels per pod. I have followed his lead in painting the surface details.

Another liberty I've taken is that I've pasted a UFP logo on the front of the station. Someone else did that somewhere, and I thought it was a nice touch. Also, I should point out that since no dimensioned drawings of the original model are available that I eyeballed all dimensions. I scaled and moved things around until I was able to reproduce rotoscope-style the reference photos I have.