40k is not about a realistic representation of current warfare, but a toy for male teens. Tanks like the Leman Russ have guns fitting only a major battleship, Catachan soldiers have square chins, enormous biceps and fists bigger than their brain and all females are sexy. You can also argue that Chainmail bikinis are unrealistic, that doesn't make them obsolete in Fantasy settings.
BTW beside the Cadian conversion set, Shadowforge also makes an acceptable unit of female Catachans:
http://www.shadowforge.com.au/prod_pages/scifi.html
Melissia wrote: I mean how many men have chest/waist/hip ratios of ~43/34/43 or so (roughly average for a woman in the US)?
US Centers of Desease Control and Prevention wrote:About one-third of U.S. adults (33.8%) are obese.
http://www.cdc.gov/obesity/data/trends.html
Maybe 140/180/140cm is more realistic