Hey, I’m the author of the minimum password length plugin and I just noticed this thread. I looked at the code from the password strength meter from the OP link and it appears that it’s only checking the password length. Is that what you’re looking for, or did you want to make people use non-alpha characters etc?
The best solution for this would likely be to utilize the existing password strength meter built into WordPress. If I remember correctly, there’s even a JavaScript library that could be queued from core that would do most of the heavy lifting. I’ll take a look tomorrow and see how hard it would be to add that to the BuddyPress profile page (and maybe have an option to force people to use strong passwords too). I’ve had limited experience with BuddyPress though, so we’ll see how far I get