I have a similar vintage bath ( but imagine pink and seashells!). You can embrace many of these elements since vintage is such a trend right now, and probably squeeze a few happy years out of it.
Exposed plumbing is trendy so don't feel the need to cover it all up. Consider getting some stock cabinet boxes to put under your sink with some shelving ( Home Depot, IKEA). It shouldn't look like a one piece vanity, it should just look like shelving. Use baskets & boxes for your stuff. Display folded towels in the awkward spaces.
I don't mind the mirrors you have. They seem to mimic the ceiling which is a nice connection. Update the sconces though! Yes Yes.
Right above the tiles, try mounting a long shelf ( 4 " deep)from wall to wall.
Mount a shelf above your doorframe as well for less used items. Use baskets and boxes. Try yellow accents to embrace your tiles.
For decorating flare, if your bold you could apply a modern wallpaper that ties grey and yellow into it above the tiles however if your bathroom has no venting and gets really steamy then don't.

i can somehow imagine pink and seashells, mmonika :) because our bath used to be horrible pink and butterflies on some kind of reflective paper and i didn't turn on the lights unless absolutely necessary :)
it's still small because it used to be a linen closet.
i think you have a good suggestion about the venting..it's really important and determines what kind of decor you can use.

These wonderful vintage bathrooms never look right with vanities or wall cabinets - at the most a glass & chrome shelf, but you already have a medicine cabinet there...
...so I'd look for other places for storage,such as a basket of rolled up towels beneath the sink - and keep the rest in the linen closet out in the hall.

Check out these link:

http://www.wayfair.com/OIA-Glacier-Four-Tier-Etagere-in-Chrome-16954-IAB1146.html

If you don't want to spend the money on shelves you could sew or velcro vintage type skirt around the sink to hide things underneath. Use a shabby chic type material, and you could also hang a shoe bag or jewelry bag behind the door for odds and ends. This would work if your style is cottage anyway.

Thanks everyone!
I was thinking of doing the fabric around the sink but when I think of those, I think of a country look which isn't what I'm going for. Shabby chic is more like it. I don't have little ones so I won't need to worry about toothpaste on it. :)

Now I need to master the art of sewing a straight line....

Yup, not much choices here - sorry, I don't like pedestal sinks - they should only be used in powder rooms, and then, where do you store extra toilet paper for guests? Pretty aesthetic, not functional enough for me. I've attached some photos for you on how to get more storage temporarily. Good Luck!