Much of this boils down to trust. Mainly due to anything put out on the web is there forever. If you wish to pursue Providers I'd suggest two things.
- Join P411 and search for Photo Friendly.
- Schedule a date prior to any shoot. It'll give you a better idea of what they look like, what they'll feel best about doing and some ideas about backgrounds/themes for them. (What I do)
If you look for non-providers you may want to join One Model Place. Many of the folks on there will do TFP (Time For Pics) to expand their portfolios as well.
http://www.onemodelplace.com/
I'm guessing that your own portfolio would be accesable via the web. I'd take GREAT care that no personal info is either displayed or embedded in the photo link. I ran across that last year and told the lady about it so the studio could fix it. If you're lucky enough to run across someone like Zasu Knight, who constantly has her "adventures" posted on her website, then you have no worries.
Lastly.....CYA. Post nothing here that hasn't been cleared with the lady or ladies. Get an email or PM with an OK.
Best of luck to you.