Advanced race guide has alternate traits that can allow for a dusk elf, and it's hinted elves with darkvision sometimes do have drow heritage. I wpuld do that, allow access to drow feats, and call it a day.
There are several alternate racial traits that you could use if your GM approves; replace low light vision with Darkvision or Blended Veiw, also there is an alternate trait for half-elves called Thinblood resilience, that replaces Elven Immunities and is flavored as belonging to half elves who's even parent was Drow.
It's a bad idea because even when you're not playing, the campaign is making stories for itself.
I would start with either Elf or Drow as chosen race and then look through the alternate racial traits for that race for ways to pick up features of the other race. If you are starting as a Drow, consider selecting Surface Infiltrator.
Half-elf. Drow blooded. Drow magic if you desire such a thing. There are racial trade-offs for each.
This is very much fluff, if your DM is willing to allow Drow then there's no reason you can't just play a Half-Elf and say that it's elven lineage is Drow.
As others have pointed out there are alternative racial traits to fit the mold but I wouldn't even say those are mandatory, your designing your mix raced character so you can decide how that presents itself with the mechanics allowed.
Background wouldn't even be that hard, love child of master and slave, father was a drow who went to the surface or mother who went and abandoned child or some Drow diplomat/spy/merchant, however you want to do it.
Play a drow. Take this alternate racial bonus:
"Poison Minion (4 RP): Drow sometimes augment their slaves and frontline warriors by making them toxic, causing their bodies to internally produce mawbane poison (see below). The resulting poisonous creature makes a potent weapon in the effort to discourage neighboring monsters. Any creature that hits such a character with a bite attack is immediately exposed to its poison. The save DC for this poison is equal to 10 + 1/2 the character's Hit Dice + the character's Constitution modifier. Mawbane Poison—ingested; save Fortitude as above; frequency 1/round for 4 rounds; effect 1d2 Constitution damage; cure 1 save. Drow can take this trait in place of drow immunities, light blindness, spell resistance, and weapon familiarity."
This gives you superior darkvision without light blindness, the drow spell like abilities, keen senses, poison use and poison minion.
That is really like being a half-elf/half-drow. You also have a built in backstory, in that your mother or father was taken during a drow raid and was brought back with them. You were born into slavery, and were augmented with mawbane poison to make you a better worker. You eventually escaped and fled, eventually coming to the surface.
Class Idea
* Unchained Rogue (by lvl 3 you get dex to damage, you make use of your +2 Dex, and it makes sense given that you were able to successfully flee from your drow masters)
* lvl 1 feat (Drow Nobility: Your noble parents who spawned you and condemned you to a life of slavery. Gives extra spell like abilities)
* lvl 3 feat (Improved Drow Nobility)
* lvl 5 feat (Greater Drow Nobility)
* lvl 7 feat (Noble Spell Resistance. Gets you back the spell resistance that you lost, making it SR 18! Then you get a further +1 per level)
Got yourself a nice tragic backstory, racial bonuses that match your character's half-breed background, and eventually you get back the spell resistance (even better than it would have been). You also get a ton of spell like abilities (constant detect magic, dancing lights, deeper darkness, faerie fire, feather fall, and levitate spell-like abilities at will). All that, along with your rogue abilities will make your character pretty useful.