Alloderm is skin taken from donor cadavers that has been treated to result in minimal body reaction to the material. However, it may cause allergic reactions, is not permanent but may last up to a year
Other acellular(non-reactive) dermis(from deeper layer of skin) matrix are available like Strattice but these are costly and may have same problems.
PermaLip is made up of soft, solid silicone which allows it to be removed at any time.It is placed through cuts at each corner of the mouth and can be put in with local anesthesia. It may cause similar problems like silicone implants with capsule formation. It may shift. Also, the sizes that it comes in will not usually give an XL look. Stacking of them is possible but also may cause sliding and mis-position after the surgery.
It is essentially a silicone shell that is coated with teflon that is placed through small cuts at corners of mouth. Once it is in place, it is filled to the desired amount with saline and sealed. These may definitely increase the volume but can have all the potential problems like saline breasts implants like deflation. The more saline is placed the firmer and more unnatural they become. These may not be available anymore.
Other lip implants have been available like SOFTFORM/GORE-TEX/ULTRASOFT but are presently not manufactured.
Please check back for I am designing and will be manufacturing an XL lip implant of greater than largest which is available now!