yeah, there is no one "perfect" spec. before you hit outlands you can pretty successfully tank, heal or even to a degree dps with any spec... however, as you get to outlands that quickly changes. you can maybe even make any of them work with a good set of gear for most 5mans. but when you hit the 70 instances you NEED a specialized spec and good gear to tank, heal OR dps. not all with one spec. paladins have no real end game hybrid spec. all that makes us a "hybrid" really is that we can spec for anything.
i suppose the closest you could come for anything pre-raid is a 31/30/0 or 40/21/0 or something like that. if you have über gear you could probably get by healing or tanking with that. also shockadins (51/0/10 or 41/0/21 are 2 i've seen) can heal and do moderate dps, but don't expect to be popular for your dps. i personaly have my main specc'd 51/0/10 for a boost to dps for solo'ing mostly. his dps with healing gear and SoR/JoR is quite acceptable for solo'ing thanks to 2.3. i beleive this spec to be very useful for group pve, solo pve and even to a degree pvp (although i tend not to do much pvp on that toon).
so in answer there really is no one perfect one that allows you to do everything. any hybrid spec you choose will either be good at one thing and minimally able to do one other thing, or just completely gimped....