What does the drink that Mio ordered look like in Episode 18 of Nichijou? In episode 18, Yukko and Mio trying to order at a cafe which is probably Starbucks. Mio's order was 


  I'd like grande white chocolate, mocha frappuccino, also I want a
  short single-shot, caramel sauce, hazelnut syrup, chocolate chip, and
  extra-whip espresso




Is the order really exist, or she just said random a coffee's name in her order?

Relevant video on YouTube.
It looks like this:


  


Yes, you can order the exact customized drink that Mio ordered at Starbucks, given if the additives are available. The receipt says (the price is in Yen):

- 1 Grande White Mocca Frappuccino   510
- Shot                                50
- Hazelnut Syrop                      50
- Caramel Sauce                        0
- Chocolate Chips                     50
- Extra Whip                    (custom)
- Total                              660


Source: http://blog.livedoor.jp/laisser/archives/52073325.html