I haven't came across one like this at all, and I have seen many dating sites (which are all as good/bad as one another).
I would suggest your friend simply tries a conventional site, like
http://www.girlsdateforfree.com/ or
http://www.freedating.co.uk/ (these are free) and just be honest about things - at least the honesty should be respected, and if they aren't interested, they'll just move on to someone else. I suspect you are right about the men not admitting things, but as a bloke of the same age, I find that sex isn't as much of an issue as it perhaps used to be, so there could well be guys of about that age who feel the same even if they don't want to admit it.