You could make a USE_BOX trace first, then, on a hit, do a SCAN_TEXTURE (without USE_BOX) trace to some target like endpoint:

c_trace(from,to,USE_BOX);
if(trace_hit)
{
vec_diff(temp,target,from);
vec_scale(temp,1.05); // make sure it reaches far enough
vec_add(temp,from);
c_trace(from,to,SCAN_TEXTURE);
}

Ty for the suggestion.
I went with the same approach as Rayp went, which works (surprisingly) decent for humanoids. I use vec_to_ent to transform the hit.x(yz) to local coordinates than compare with minxyz/maxxyz etc. I can check for torso, head, (roughly) arms and legs this way.