A bag like a Birkin 25...but with shoulder straps?

Hi,

I've come to realise I like the proportions of the Birkin and that you can mostly have it open for access but also can be folded over and fastened. I kind of want a 25cm Birkin to just hold my Kindle, wallet and phone to take around town for brunch, coffee, meeting friends etc. My lifestyle is pretty casual and I already have formal bags (that don't fit a Kindle) to take to very formal dinners or other people's weddings.

But I can't deal with the no shoulder straps on the Birkin, and I'm not willing to engage in showing my worthiness to the Hermes store.

Is there a bag that's proportionally similar to the 25cm Birkin (wider than tall, and 20-30cm wide), can be secured, and crucially - has shoulder straps that can be adjusted? I was looking into the Celine luggage nano and was shocked that the shoulder straps can't be adjusted and you have to tie a knot in it.
 
Have you thought about a kelly 28? I know buying from the store is not your thing, there are a lot of very very good resellers, such as sandiaexchange (whom I have known for more than 10 years and such a nice lady), from whom you can buy from without the hassle of getting one from the store. :tup: