Well first of all, there are many, many ways you could approach this. If you are working with NURBS then n-gons are not an issue, as n-gons are only relevent in poly modeling. unless you mean n-gons on converting from nurbs to poly. You could definitely create cross sections and loft the nurbs, but that is pretty time consuming to get all the proportions correct. Also texture mapping can be trickier.

 I know maya's modeling tools much better, but the principles should be the same. For speed, if it were me, I'd take photos from top down and side, then set them as image planes for reference. Then I would take a poly sphere and rotate it so that the poles were aligned along the horizontal x-axis (lying on it's side). Then I'd create a loose grid deformer around the sphere and push vertices around to match the reference frames