>>2841122On apsc sensors you can still fiddle with the old 85mms you can find around, it will be more or less comparable to a 135mm, but on m4/3 they start to really be a bit too long (even if I like to fiddle with the 180mm 2.8 AF, I recognize it is not the most versatile lens, even if just for portraits...)
So I don't really have an answer: I can just say that if it was me and there weren't reasonable priced lenses for my needs, whether in its own lens lineup or 3rd party, I would just change system.
Maybe picrelated it's what would fit better in your case.
The smaller the sensor the harder it is to find gems for cheap in vintage lenses, unless you're searching for supertelephoto eq lenses (300mm f/4s =600mm without teleconverter hnnng).