not cheating
""In my current campaing we have PCs adventuring together of levels 3-12 the higher level charcter do tend to rule the day and bring along the less experienced characters in thier wake""
Well, I would never play in that kind of unbalance game. And I can speak for my friends too. I think it would be so frustrating to play a PC that is useless, it would simply be a burden for all the higher levels PCs. And in fact, in all the games that I have played in, this would be impossible.
It is not cheating to start at a higher level to adapt to a particular adventure. I played and GM games that it was necessary.
Of course, starting a character at level 1 and play it all the way to higher levels add something special. Right now, I am shoping for material to GM a campaign from first level to 20.
I hope the characters will survive long enough to achieve level 20. But in a decade of playing D&D, I never saw that. In our games, playing a PC from level 1 to level 20 would be a miracle. There is not too many chance that I see that with my own eyes.
And now, with the higher cost of Raise Dead and Resurection...

Players have the choice to make another character one level lower than the others. Or, if they can afford Raise dead and they want it, they keep the same level but before continuing advancement with XP, they must pay a debt equal to the "should be" level lost from the spell.
But hey, that is my opinion. What's important is to adapt the game to the needs of the gamers to simply have fun. And everytime someone starts a new campaign, there's always some modification to our house rules.
Ciao!
BASTON!!!