It's pricier, and not for mundanes, but you can get a skill of 12 at character creation. Aptitude to get it to 7, 4 points of improved ability, and a reflex recorder. Not possible in SR4, where max levels for improved ability rounded down and skills had an augmented limit, but very doable in SR5. You would probably hit your limit a lot, but either splitting your dice pool like Jack_Spade suggested, or spending Edge on more important rolls, could mitigate that.
Technically that's not Skill 12 either. That's Skill 7(8.)+4D6... but you are getting 12d6 to add to your Attribute for the Test.
Is it really ? improved ability page 309 SR5:
This power increases the
Rating of a specific Combat, Physical, Social, Technical, or Vehicle skill per level of
the power. You need to know the skill in order to buy this power for it, and you can’t buy it for skill groups. The maximum
improvement possible is your current skill level x 1.5(rounded up).
My reading is that original ability of 6 with aptitude 1 and 4 levels of improved ability and a reflex recorder would make it 11(12), not 7(12), making it illegal at character generation because the maximum skill rating of 6 (7 with aptitude) applies... Of course as the game evolves its pretty clear that its very cheap karmawise for adepts to evolve into combat skill powerhouses because of increased ability adept power, but straight out of character generation adepts need to play by the same rules as everybody else, and increased ability at character generation is actually a trap because of this.
Was this ever clarified?