In QCAD 3.0.3 snapshot release the ' dgn' file format has been added to the list of file formats that QCAD 3 can open (dgn is the default file format used in Microstation).
File > Open > open drawing - dgn is added to the formats.
@Andrew, thanks for this as I get a lot of dgn. files coming through for laser cutting!
I`ve just tested this and so far so good