Need a better PIN/password device lock app...

[monkeyboy]

Looking for a free or cheap device lock program for WM6/PPC/Touch that:
1) is persistent (auto starts on boot up, hangs around to make sure the device is locked when intended),
2) allows the auto-locking if the device hasn't been used in 4 hours,
3) unlocks with a simple PIN (preferably presents a large touch dial pad to enter the PIN),
4) has ABSOLUTELY NO OTHER SIDE EFFECTS.
The PIN lock included in WM6/Touch doesn't allow a 4 hour setting, and, much worse, has some very serious side effects: if enabled, it alters the behavior of coming out of standby (always ends up a Home/Today instead of the last used app). Also it seems to introduce significant wakeup lags.