Planning an Encounter, Need Advice

[Noedig]

So in an effort to get ahead of the curve so to speak, I want to plan an encounter that my party of 3s and 4s won't face until 10th-ish level. What I have in mind is a mirror of the party; Wizard, Rogue, Fighter, Cleric. Thematically, these are the four head members of a splinter faction of the church of Kossuth, so I want them to be pretty hardcore, but not insurmountable.

My plan is to have the cleric in the back of the area, buffing/debuffing with widened spells, and throwing out healing on occasion. The fighter and the rogue are going to be aggressive melee, and the wizard is going to be blasting the crap out of them from a distance.

What I need from the playground is reasonable build suggestions, spells and tactics that a group of enemy adventures would use.

[NOhara24]

So in an effort to get ahead of the curve so to speak, I want to plan an encounter that my party of 3s and 4s won't face until 10th-ish level.

So are you aiming for a TPK or...?

[Machinekng]

Seems a bit early for plannng a climatic encounter. Come back to it when the party hits level 7 or 8.

[Noedig]

I reached a similar conclusion after about 6 hours of trying to plot out every configuration of gear and spells they could have. Its way too early to tell.

[Mastikator]

The enemy party scrys on them and ambushes them when they're unbuffed and defensless. Maybe their goal is to rob them blind and will only use deadly force if necessary.
Taking all their stuff and leaving them half dead is pretty hardcore right?