Could Invision create a link in the ACP where if you knew the members e-mail address you would just have to click on a link to send them an e-mail with their username and password? It is a pain in the butt when the members know neither login information

There is no way for IPB to obtain the password - it is hashed, not encrypted (and thus cannot be decrypted).

Maybe it could send them the forgotten password link??

Or Generate them a new one...