DIY Bandeau: This links to a Danish blog, but the jist of what it says is to sew a wide strip of elastic lace together and then just slip it on over a strapless bra...which is kind of ingenious really.
Have a tank that doesn't fit quite right or just needs a make over?? Add lace (or coordinating fabric if you prefer a more modest look) and you've got a whole new shirt! // original photo source not shown. :(