Short nose R180's from NA S13's and the front diff's from Navara's, Pathfinders and terrano's have 27 spline output flanges. They are bolt in style though and 6x2 bolt flange pattern. Only the short one from the 4wd's is useful though, as one is around 2 foot long as the diff is offset a long way to one side. The S13's output flanges are 27 spline and are circlip style, but the flange pokes out from the diff about 2 inches each side which will impact on what shafts you can use.
I have put a long nose R180 from a 720 4wd with a NA s13 short nose Tomei 2 way LSD into my C210 Skyline.
What I did was use 2 short output flanges from a Terrano front short nose R180. I had the tips of 2 NA S13 output flanges cut off at the circlip groove. I had them drilled and tapped to suit the Terrano flange's bolts, and bolted them to the end of Terrano output flanges. I had the Terrano flanges tips machined prior so that the circlip groove would be in exactly the right place.
I used the Terrano output flanges instead of the NA S13 ones because they are flush with the diff and don't poke out as much. This makes finding factory shafts a lot easier. You get around 2 inches extra length of shaft to play with on each side with the Terrano flanges.
I then used NA S13 cv joints on the inside end of the axles.
The shafts you use will obviously depend on the car it's going into, but I used R30 shafts with R30 cv's on the outside as it's all mounted in an R30 cradle. I have a different setup in my 240z so I can't be sure what shafts would suit, but I think 2 x R30 short side shafts may be close to fitting. From memory I think they were 390mm and 400mm. NA S13 cv's and R30 cv's share the same shaft spline size and count.
I'm not sure about the flange on the wheel end, but I think R30 flanges may fit in place of the 240z flange so that it can bolt up to the R30 cv. If not the you may be able to squeeze an adapter flange inbetween.
Alternatively You may be able to use subaru r180 inner cv's with R30 short shafts. I have not measured this idea, but It would be worth looking into if you can get the cv's with a subaru diff.
Getting custom shafts made is not overly expensive though. I had a pair shortened and resplined for $360. I was told I could have a pair made from 4140 for not much more, about $400.