While working on the subject of still some work to be done to DXF/DWG file import/ export; I imported a "man" 3d mesh model in dxf format into CU (build 660 - OSX).
The dxf which was originally something like 24mb... ended up as a CU file of almost triple that size. Nothing was done to the CU file, just save after import.
I understand there is some overhead for layers and relations and all, but as everybody knows a CU file of more than 20-30mb can take even the best computer out for "a spinning beachball".

Any tricks to avoid this overhead?

sorry, but te CU file was 70+mb and crashed on opening after taking 20min.. so Ill e-mail you the dxf file instead so you can test yourself. I did not find any polymesh option in "poser" (v.7 current), but I can ask them if there is another trick to export.

Anyhow the dxf import is probably not the best as the meshes are very rough and the Rhino file (from the Poser 3ds export file) is very much smaller and much much smoother in CU. From Rhino the names of the mesh surfaces is also kept on import to CU so its easier to select and colour bits and pieces. The dxf is just one big item with hundreds of thousands of small mesh bits as you say.

Thanks for giving it a try. I have been looking around for a proper surface or solid model of a typical "human", but so far have found nothing that looks somewhat "human" and not like "a wooden toy".

Seems other are looking for the same in this forum though.