The legacy champion and uncanny trickster(weapons of legacy and complete scoundrel, respectively) both have the ability to advance the class features of other classes. There is a general disagreement if this can advance classes beyond their normal max level, but i believe it can.
normally, this is used to abuse classes like the hellfire warlock, gaining absurd amounts of bonus damage to your eldritch blast.
now, however, im going to abuse the fact that, beyond this nifty feat, they also have abilities of their own.
step 1: qualify for both uncanny trickster and legacy champion. trivial. i recommend rogue or factotum for this, since skills can be useful for this build.
step 2: take a level in uncanny trickster
step 3: take two levels in legacy champion, advancing uncanny trickster, advancing legacy champion, advancing UT, looping until LC 7, where they lack an advancement
step 3: take another level of legacy champion. loop until you know every skill trick in existence. pop the final advancement gained into factotum/rogue/whatever you used to qualify.
my build would look like factotum 10/UT 1/LC 3/Factotum 6
17th level factotum abilties, all free feats(FoI, WOOT), and all skill tricks known.
Nice?