You need to be level 25+.
You have to pay
Up your level, or if you don't feel like waiting, spend your gold.
It's not on level 10 because loads of people are way past level 10. It is actually unknown what level the quests start.
You have to unlock Russia first, then that unlocks the tattoo shop!
Quests are not available right now but it will come soon. Until then, be patient. This answer was written on may 17 2011 so quests could be available now.
do research
no
you research it
Go to tom nook's shop and talk to him, say "Show me the unlocks" and take "Restaurant empire, and he will build it soon.
Yes, You unlock them by advancing in the Story.
When you level up, you unlock a little section of the restaurant. When you get to level ten, you unlock a side section, which you have to buy. This will keep expanding and get more expensive.
you need to acheive different tasks in order to unlock diffferent armor. You also need to get achievements