For lock screen apps, there's a good roundup of options at tested.com, depending on what you're after you can either augment the lock screen to act more like the home screen or tweak the settings to allow more flexible locking approaches.
If you want finer control over when to use the keyguard and when to use simple sliding or no locking, look at Tasker, it allows you to define a multitude of rules, for instance disable the keyguard when a particular Wifi SSID is detected and enable it otherwise.
For your other question. MobileDefense is apparently very good, but as you've pointed out is currently in closed beta. As an alternative to MobileDefense, consider Wave Secure. It allows remote locking, wiping and tracking of your phone.