In search of optimum tradeoff of noise and resolution in a 5 megapixel resize of NEX-5 and NEX-7 images, I tried a series of averaging operations before the resize. The one that worked best for the NEX-7 test image was a 2-pixel box blur in Photoshop followed by a resize in Perfect Resize using the default parameters. Even so, the results were inferior to the reference D3s image — both noisier and not as sharp.
The crop of the NEX-7 image looks like this:
The crop of the D3s image looks like this:
Included for completeness is this crop of the NEX-5 image, although the 2-pixel box blur is too broad for the 3:1 downres: