Ranger/Paladin spells earlier than 4th.

[Herobizkit]

IMC I allowed a player to copy the spell progression of the Blackguard starting at 1st in exchange for dropping armor proficiency to Light armor (and included all shields). Worked fine for me.

I'm a very liberal DM though.

 

[Claudius Gaius]

Well, all of its going to be more or less "unofficial" - or at least obsolete by WOTC standards - for current D&D as soon as fourth edition comes out. If the players really want to trade around class features a lot, the shareware version of Eclipse: The Codex Persona has them all broken down for cost.