Well! With this site, you can make those tweaks to a piece of clothing before you get it at home (aka, no making a whole other trip to a tailor).
Here are some picks I have my eyes on...

Reminds me of J.Crew's tissue garland tank and Anthro's Storybook tank
Yet, cheaper than both.
And on this tank, you can chose the neckline, length and sleeve options (turn this tank into a long sleeve shirt, if you want!)

But, $50 less! And customizable...
For this dress, you can pick from tons of different sleeves and length of the dress.

Love the ruffle detail:


Chose the between below the knee or above, and enter your height for accurate measurements.
This site even has great accessories! And going on now through 2/14, but any 2 items, get the 3rd 30% off (the lower priced item) - not including jewelry. Check it out...