Greetings and Salutations. The first thing we need to understand is that Palladium has a few different versions of werewolves. This is important, because a few of them are handled differently. The werewolves we see in the Conversion Books (and also a werejaguar NPC included in Vampire Kingdoms) are treated as inhuman monsters. This concept can be interesting, but it also goes with the mentality that they're just instinct driven monsters (even if not evil) that don't really advance. Vampires don't really level much either for that matter.
While I'm not the biggest fan of PF werebeasts, I will say the thing I do like about them is they're treated more like individuals and can do things like take an O.C.C. Within Rifts all a certain type are all the same way ... which while okay for villains makes them not as interesting as characters (which is a personal preference thing, and I understand others like the evil monster thing).
For simplicity, I have included a list of the various werewolf (werebeast in general) write-ups I know of in Palladium. Palladium Fantasy, the Nightbane options (both of them), Heroes Unlimited (super power), and Zenith Moon Warpers (not actually werewolves) are the only ones I believe that have the potential to level. The Beyond the Supernatural and Rifts versions in general are instinct driven animals, and they won't level anymore than the horse your character uses as a mount.
If you want a leveling system, you'll probably have to make it up yourself. In this case, I'd suggest handling it the same way Palladium handles vampires leveling really, because in Palladium they're both just instinct driven predators/monsters. Both would rely on their natural abilities and instincts, with little use of technology and human/mortal means (because they feel those are inferior to their natural abilities and instincts).
Anyways, I think that about covers things. Hopefully some of that helped. Thank you for your time and patience, please have a nice day. Farewell and safe journeys for now.
1a) Beyond the Supernatural (original/first edition): They have three forms. Natural race.
1b) Rifts Conversion Book One (original/first edition): Converted from Beyond the Supernatural (not PF). They have three forms, and normal P.S. (though their claws can do M.D.). Natural race.
1c) Rifts Dark Conversions: Converted from Beyond the Supernatural. Updated/revised version of the stats in Rifts Conversion Book One (instead of putting them in Revised, where they are missing, they were put in Dark Conversions). They have three forms, and now have Supernatural P.S. Natural race.
2) Palladium Fantasy: Only two forms, can only transform at night. One is a human form and the other is a giant wolf form. This is definitely true of Second Edition (First Edition may have been human/man beast form, it's not 100% clear, it could be human/wolf form too). Normal strength. Natural race.
3a) Nightbane RPG: Nightbane ARE the werewolves (and other types of beasts). There is a Lycanthrope table and everything. Only two forms, and Supernatural Strength. Natural race.
3b) Rifter 4 & 5: Optional Rifter material adding a separate race of werewolves (and other types of beasts) into Nightbane. They have three forms, normal strength, and are based more or less off of the BtS version above, but have some differences and they have a few specialized O.C.C. (which is a plus). Normal strength. Natural race (I believe, I never did read the article).
4) Loup Garou: Rifts Canada (Book 20). Three forms again, can transform at any time. Supernatural Strength. Natural race.
5) Heroes Unlimited: There is a Super Power Lycanthrope. It's not quite the same as it's only a super power, but still to be considered. Only two forms (human and man-beast) and possesses Supernatural Strength. Super Powered individual.
6) Lycanthrope Curse: This is not a race, but is a curse. Turns the victim into a blood-thirsty wolf on a full moon (victim has no memory of transforming). This is detailed in PF, not sure if it's included in any other systems. Normal strength. Curse/affliction.
7) Zenith Moon Warpers: Not quite werewolves, but similar in appearance. They have the natural look of an attractive man-beast, but can take human form. Supernatural Strength on Rifts Earth (but not weaker magical environments). Natural race.
Living the Fantasy (fan website)
Rifter #45; Of Bows & Arrows (Archery; expanding rules and abilities)
Rifter #52; From Ruins to Runes (Living Rune Weapons; playable characters and NPC)
Rifter #55; Home Away From Home (Quorian Culture; expanded from PF Book 9: Baalgor Wastelands)
Official PDF versions of Rifter #45, #52, and #55 can be found at
DriveThruRPG.