I suppose it's planned with the layer system, but be able to change the display detail level per object/layer would be welcome for this kind of work too.
This kind of details in nurbs is really heavy, but the exported geometry can be really light with the right settings in the meshing (hyperthreaded :o)) tool.

Displacement map can give great results, with the right engine ... but not that many renderer can do good (and fast) displacement map out of the box . The setuping time can be long too .... displace baking, probably normal map baking if the engine can't do microdisplacement map (like lightwave :'( ) or native 3dsmax). Without saying some uv's seams fighting ... all in all I often prefer to build the detail in the model too.