Here are a few examples of such networks that are actively recruiting new members. I will expand the list into a more comprehensive one when I have the time. So just three for now.
Bloggerlicious is a brand new forum created by CheapSally.com. They will start campaigns like paid posts once they have 50 members in the "Interested in Bloggerlicious Campaigns" group (currently 30). After you register for the forum with your site information, apply to join this group and you will get a notice about whether you're accepted. Good luck!
2. Sublime Media Connection
Sublime Media Connection is a relatively new blogger community. I've been a member for 2 months and really love my experience. Not only does SMC give you exclusive access to review and giveaway campaigns, and paid post opps, but more importantly it encourages members to support one another through hops, comments, retweets and resources sharing. It's not completely free, but the $2.50 monthly fee is highly affordable and well worth it. Please let SMC know that "icefairy" sent you when you join. Thanks!
3. Mamavation Forum
Mamavation Forum has been around for a well. It's an integral part of the Bookieboo network. It's a great place for bloggers to mingle and to be the first to find out upcoming Bookieboo blogger campaigns. Join by 8/10 and you could win $100. Find out how here. Giveaway is for new members only.
Hope to see you soon in one of these networks! Happy blogging!