I don't know about cajones, but there are some build issues I need to think through before I do it. I want to build a "gear down" version so I need to figure out some way to strengthen the landing legs so it'll stand up without the clear stand that uhu02 shows. I think there are also some ways to make the landing gear more accurate.
Also, I need to figure out a scale. I made some inquiries here and at the other card modeling forum some weeks ago and the consensus seemed to be that the model is 1/100th scale. Or 1/96th. (Any chance of asking uhu02 himself?) I'm giving some thought to building it at 1/72nd, but have some reservations. The larger scale would allow for more detail, but it would also require more scratchbuilding. The landing gear would have to support more weight, and I fear that size could well be the limit of what might look good with paper.
In looking at some detail photos of the "real" Aries 1B it appears there are some areas of the model I'd need to make more accurate. That's not a knock against uhu02's excellent work, but just a statement about what I see in photos compared to what I see on the model. There are no huge accuracy issues, that I can see, but some small things, like the shape of the RCS quads. (Or more accurately, I guess they are RCS "quints" because each structure has five nozzles.)
I would probably skip building the passenger cabin and do only the flight deck. The "red light" version of the flight deck looks pretty cool....
I've still got to think these and other items through, but I've always loved the Aries 1B and wanted one in my collection. When I was building in plastic, the available kits were expensive and/or hard to get. Then I switched to card and uhu02 came to the rescue.