Even PC's built by the DMG guidelines are tough. Building one to full PC specs would give you trouble, especially at higher level. consider a high level PC as an adversary:
- No incentive to save dailies/enounters/AP's, so combat goes daily, AP: daily, daily, daily, encounter, enocounter, etc until dead.
- PC level damage and utility
- Lower HP's than a monster. Much lower.
If you did a party of PC's, it would be a 50% chance of a TPK, and likely a party member *will* die. Imagine how fun it would be for an Epic Orbizard to stunlock your character. Yay, you might as well go home! Or if an epic barbarian decides to nova on your PC, he might as well rage strike, and take the 9[w] rage strike at that.
Even at lower levels, the adversary PC's have no incentive to guard their resources. At 5th level each NPC can use their two dailies in the first round. Do you want Lead the Attack on you for an encounter? Guess what, you've got it, and more. Add to that the PC healing being in the enemies hands, and you have a swingy, deadly encounter waiting to happen.
Even the NPC guidelines in the DMG make for a fairly tough fight. I would use those as reccomendations for how to allocate powers, but stat up your enemies as full on monsters with a monster stat block instead of power cards. Use the mechanics of the powers you want to emulate, but with to hit and damage values more in line with a monster of their level. They will *seem* like enemy adventurers, but it will be a lot more fun for you to run and for them to play.
Notice, I did not even get into the complexity of trying to run a party of adventurers *by yourself*. Yuck.
Jay