If you are serious about fashion work you need a set of fast primes, not an f/4 or slower zoom. Although the example you linked to is impressive considering it was taken using an f/4 zoom, it is probably not quite good enough for commercial use.
Depending on what focal lengths you plan to work at you can go for any of the following focal lengths. 35mm, 50mm, 85mm, 100mm, 135mm, and 200mm. You probably don't need a lens in every one of these focal lengths, but you probably do need at least one wide, one medium, and one long lens.
Lenses like the $360 EF 85mm f/1.8 perform every bit as well optically as the $2,300 EF 70-200mm f/2.8 L IS II set at 85mm and using the same apertures, plus the prime is over a stop faster at f/1.8. The EF 85mm f/1.2 L II, at about $2,200 is six times the price but delivers incredible image quality that no current zoom can touch. The comparisons are similar at 50mm: The EF 50mm f/1.4 costs about 1/5 the price of the $1,620 EF 50mm f/1.2 L. The 50mm f/1.4 set to the same apertures is the optical match of the EF 24-70mm f/2.8 II set to 50mm.
Based on the assumption that you are shooting on a full frame body I would recommend starting with the EF 50mm f/1.4, the EF 85mm f/1.8, and the EF 135mm f/2 L. You can purchase all three of these lenses for about $500 less than the EF 24-70mm f/2.8 L II and only about $300 more than the EF 24-70mm f/4 L IS. If you just must have a zoom, you should consider the Tamron SP 24-70mm f/2.8 Di VC. It debuted at around $1,200 bucks around a year and a half ago but is now selling many places for right at $1K or less. It is not quite as sharp as the Canon 24-70 "II" at longer focal lengths and f/2.8, but it is better than the original EF 24-70mm f/2.8 L and much sharper than the EF 24-105mm f/4 L (which happens to be my favorite general purpose lens, but I would never consider it for paid fashion work). By f/4 the Tamron pretty well matches the Canon 24-70 "II".
Here's a comparison between the Ef 24-105mm f/4 L IS, the Ef 24-70mm f/2.8 L II, and the Tamron SP 24-70mm f/2.8 Di VC at DxO Mark. The overall scores are weighted for things, such as absolute T-stop vs. claimed aperture, that may not be your primary concern. To get to the actual data click 'Measurements--> Sharpness--> Profiles' and then select focal lengths and apertures for each lens. The two 24-70mm f/2.8 lenses are clearly sharper than the 24-105mm f/4 above 35mm, especially at the edges. At 70mm focal length the Canon 24-70mm f/2.8 II is sharper at f/2.8 than the others are at f/4. By f/4 the Tamron is pretty much the equal of the Canon "II". You have to stop down to f/8 before there is no real difference between any of these lenses. Clicking on the 'Measurements--> Sharpness--> Field Map' and setting each lens to 70mm/75mm @ f/4 illustrates the differences dramatically. Swapping in the EF 24-70mm f/4 L IS shows the new 24-70 is slightly better than the older 24-105, but still trails the two 24-70 f/2.8 lenses at wider apertures and longer focal lengths.
Be aware that no matter what lens you use in order to get results similar to the example you linked you are also going to need some studio lighting with quality modifiers that allow the light to be softened and spread over large areas. You are also going to need to do a significant amount of post processing, particularly in terms of selective sharpening and frequency separation, to get similar results.