I'm developing a WordPress site right now with a highly customized login/registration system. Mostly, I've been successful in accomplishing this through a combination of plugins, hacks and, well, just plain moving things around. I've moved validation to the front end via jQuery, for the most part. But one thing has got me: When, say, users enter the wrong username/password combination, they get redirected to wp-login.php. That's not what I want -- I want an inline error message to appear under the form. But I haven't been able to find a plugin or any other code that will do that for me, despite much effort.
Any ideas? In a nutshell, all I'm really doing is copying the standard WordPress login and registration code and pasting it on a new page (which also includes other content; that's why I can't just skin them). There are other things at work, too -- extra fields and whatnot -- but those shouldn't be too important in this context.