Back in 2008 or 2009, I took an organists tour of Switzerland, Alceis, and Germany. We averaged two or three instruments per day, and everyone who so chose got to play on each instrument. The exception was Wittenberg, because they were having roof problems. Sib-in-law had to sign a very long waiver that said, in essence, if something falls onto your head while you are playing, you won’t sue us. This was before I had a digital camera, so I didn’t take pictures.
(Digression) One thing that surprises people is how small true, unmodified Bach organs are. The churches were also small, and constructed with acoustics for instruments and human voices. They can still shake your bones with sound, but your ears won’t hurt. (End of digression.)
Since then, I’ve been able to visit and sometimes hear instruments, but not play them.
What we see in the following photos is the casework. It is very difficult to get up and look at the “guts” of an instrument, because it is cramped, elevated, and delicate. The casework holds both decorative and sounding pipes, and supports the decorations around the pipes. Modern casework tends to be plain to the point of severe. However, I’m going to focus on Baroque, Rococo, and reconstructions of older styles. Organs are a sort of “gesamtkunstwerk,” meaning that the pipes, loft, accessories like a zimbelstern and chimes, and case are part of an entire work.
We’ll start with an organ from Luneberg, Germany, south and east of Hamburg.

It is a relatively small instrument for the space, but the caswork is excellent. You’ll notice that the organ is comparatively “flat,” in a straight-across loft. Most organs are built flat, or with the central pipes forward of the sides. That’s not always true:

Cathedral organ in Rostock, Germany.
Because of restoration in progress, I could not back up far enough to get my usual organ photo. What you see at the bottom of the photo is the roof of the prince’s box. You have to crane your neck to see the organ itself, waaaay up there, and curved “backwards” as compared to most instruments. It doesn’t seem to affect the sound as heard from the floor of the church, but I suspect that there are some interesting dead spots unless additional pipes have been added at remote positions.

Looking “up the skirt” so to speak of the organ in the Cathedral in Rostock. The prince’s box is directly below the organ, making me wonder if he heard anything at all or just felt the vibrations.
You can see some of the scaffolding on the right side of the photo.
What you don’t like to see when you ease into a church to get pictures and just look around:

St. Michaels, Olomouc, Moravia, Czech Republic. They are restoring the ceiling and upper walls.
You can’t get there from here, or there, or over there, either. SIGH.
OK, back to organs. This is in the lightly-baroqued church of St. Thomas (now Protestant) in Tribsee. 
The case and organ are reconstructions. The neo-gothic case is very simple, but sensitive to the gothic “bones” of the church. Flat mounting, because this is a relatively small instrument. That’s good, because the space is small and very resonant. It is possible to over-organ a space, believe me. It is a relatively light sounding instrument with a modest “bottom” of pedal stops. The church was originally Cistercian, then re-done in a tasteful Baroque, turned Lutheran, and restored to the gothic with some Baroque elements left.
This last one is not North German, but southern and eastern. However, note something very unusual:

Organ behind the altar? Huh?
This is from the Market Church (Church of the Holy Ghost) east of Goslar in Clausthal-Zellerfeld. The church was reconfigured for Protestant worship after reconstruction in 1634-42, then returned to Catholicism later. The organ dates to 1642, and has 41 registers. It is the only church I’ve seen in Central Europe where the organ is behind the high altar. This is also the largest hall church in Central Europe. (The organist had a very large pair of placards describing the problems with the instrument and begging for funds. It is a historic instrument with some original elements.)