Is it possible to access a bgeo file from HOM?
Without an actual fileSOP?

There currently is no way to read a bgeo file directly into HOM. This currently exists are RFE 35232: hou.Geometry.loadFromFile()

Thanks Graham!
I second this and submitted a RFE, too.

Is it possible to read a file into ANOTHER hou.Geometry instance?
How to create hou.Geometry instasnce object, which is not bind to any SOP node?

code as
new_detail = hou.Geometry()
throws an exception ~“constructor is not implemented”

we solved this problem with really complex solution, but may be there is just simple magic spell to get what we need?
Thank you!