Wilson Combat is announcing what they call the "Toughest Ambi Safety You Will Ever Find Anywhere" It's made of billet steel that has been CNC machined for 'long lasting, wobble free fit'. It's pre-shaped, available in blue and stainless, is contoured for proper ('perfect, comfortable') feel and held in place by a hammer pin that holds the right side lever securely in place without using the grips to hold the safety in place. Fitting is required.
Buy yours here. They are also running a special on 1911 grips if you are interested.
Note: Adding this ambi safety to your weapon will do no more to improve your marksmanship and gunhandling than it would to smear the weapon with peanut butter if you don't train properly...one might even argue this applies to just about any weapon accessory when it comes to the fundamentals.