MOD EDIT. MOVED TOPIC
I would go with the model that @urodacus mentioned, it's got the red dot award, that's a sign of, it's awesome. However, it will be expensive.
To answer your second question, yes and no. If you want to brave ruten and leave comments on their pages, yes, you can check availability. Most bike shops will not have an online shop that will show available stock.
Easy way around the aforementioned problem is, check the major brands (Topeak and Lezyne were mentioned). Make sure you are browsing their TW website and see if they have a list of stores that distribute their product. I know for a fact that Giant is a retailer for Topeak! Most things that you find on the Topeak website, will be available in the Giant store. If not, they can always order it for you.
I would not rule out Giant or even Merida branded pumps. They are most likely manufactured by the big brands and the two brands just slap their name on the product.
Also, one thing to keep in mind, the longer the pump, the easier to pump air into your tire. Downside is, the long pumps aren't cooler/sleeker looking than the shorter ones.