My GF uses a vetta gel, fairly wide, though I don't know if its women's specific. Ye could start with having a look at Terry saddles- they were they first women's saddles that I remember seeing; and check Specialized ladies equipment as well- I know Wiggle have a Women's section on their webshop- CRC may have too.
I'd have a trawl too of Google, see if you can find reviews- What Mountain Bike and MBUK have ladies sections in their mags, and see if ye can find info on women's equipment on MTBR.com.
I'd second Andrew as to good pants/shorts- my GF has loads of links for running gear, I'll get them off her later.
Another thing to try may be Triathlon sites/suppliers, since it's a very tech. sport with high female participation.
Cheers for now,
Dav