So six Mews are not an option? Tempted to try a team like that but am afraid I'd forget what Mew had what moveset.
As for other options maybe try a Nincada/Ninjask. Fast, hits 'hard enough and can support team late game with baton pass. Scyther is worth a look: fast, strong can be buky w/eviolite, can utilize weak early game moves well with technichan but is held.in.check due to his typing. Togi line for.serene grace abuse.
Will leave off, typing on phone w/chubby gaming fingers can get annoying.
My last playthrough was an Eeveelution team. Vaporeon, Jolteon, Espeon, Flareon, Glaceon and Leafeon. Fun times.
My game before that was an odd mix, as I was playing the game only using pokemon I could find, rather than what I do in subsequent runs, breeding a hand-picked team and trading the eggs over. I ended up with Magnezone, Jellicent, Dream World Cincinno from that grotto, Unfezant, Reuniclus, and a sixth that I can't recall atm (wasn't a starter though)
My most recent team that's not long started is Voltorb, Tentacool, Slugma, Zubat, Ralts and Mankey.
Hey, just because they're hand-picked doesn't mean they need to be OP pokemon. Campaign is just campaign :P
Pokemon White FC: 3568 3549 8596 Pokemon Black 2 FC: 1593 3074 6920