My games are probably more politically laden than some D&D games, but not necessarily in the "political intrigue" style you're looking for.D&D seems to be quest orientated - go to x, kill, fetch or otherwise do something to item/person/monster Y return for reward Z.
Personal goals seem to be more of a 'backstory' type thing and seem to be relegated there.
Here are some links to the sort of game I run with 4e. I certainly don't agree that personal goals have to be relegated to the background; I think they can be at the forefront of play. But D&D's action resolution mechanics tend to mean that things tend to very quickly turn violent or magical; and the greatest diplomats of the age are likely also to be the greatest warriors or wizards (think Aragorn, Farmir, Gandalf, Arthur, Robin Hood, Odysseus, etc).
My personal solution to this problem is not to have the NPCs level up, but rather to scale up the opposition - at low levels, the politicking involves bandits, or petty death cultists, or whatever; then at mid-levels you tackle their Saruman-like wizard sponsors, etc; then at high levels you tackle Orcus himself. In other words, I think for political D&D to work it is better to embrace the gonzo cosmology than to try and work around it.In all honesty, I would think twice before running a political game with D&D. The assumed rapid escalation in PC abilities relative to everyone else creates problems - if the NPCs are lowish level then challenges that are tough at low level rapidly become trivial; if the NPCs are highish level, the question is likely to asked why they didn't dominate the PCs as soon as they came on the radar. And if the NPCs level up alongside the PCs, that runs the risk of cheapening the PCs' achievements