Hello Artwatch,
Well I know CanadianBitcoins has an option to sell bitcoins back to them, but I had never tried to sell any bitcoins, therefore I do not know the process myself.

To get steem to bitcoins you can use ShapeShift.io
Watch this video on YouTube starting at 1:24:00 time.

There you will be able to see how to transfer from Steem to Bitcoin, and if you watch further there might be even more information that you like, such as how to get a Bitcoin credit card.
I hope this information is useful to you. I didn't do any of this myself, but these are the options that I came across.
Good luck!!