Well... here are my thoughts. I assume that you are aware of how passive is formed in German and that there are 2 forms of passive, of which werden + past participle is one.. called "Vorgangspassiv".
The reason why something like your example is rare in written convo might very well be the fact that the author does not know when exactly it will be read... so writing "is being Xed" or "wird geXt" respectively is dangerous because it might not be true anymore.
As for spoken German it can be found there, too... maybe with an indication of time added.
Bei mir wird gerade/seit 3 Wochen/ ab morgen gebaut.
Die Post wird gerade abgeholt.
So I would say the use is not much different to English. If something "is being done" then it "wird gemacht" in German.
As Germans are pretty lazy with their future tense as long as time info is given "wird gemacht" can also be a future tense... so that would be "will be being made".