coinpayments.net seems like a good one. There are a lot of sites there. I'll pay $5 SBD for this response, assuming that when I do my verification at the end they are legitimate websites accepting STEEM.
https://www.bitwala.com/ seems like it is not live yet. If it is, can you provide more details to prove it meets the terms in the post?
RE: Let's build a list of websites/businesses/services accepting STEEM/SBD as payment - Paying 1 SBD per qualified response