Recently Samsung have release a dual sim S5 only at China only. Reason is I can think of maybe it is manufactured there and would probably cost less to have China as test market afterall they have a large group of consumers. Or maybe I'm wrong at Xiaomi is currently the most wanted phone at China due to it's power pack specification and low price compare to Samsung or Apple.
Anyway Samsung decided to have an international release of S5 Duos and Middle East region is chosen to be first. The specifications for the Duos and normal S5 are exactly the same except for additional slot of sim card. Both phones are LTE capable.
Price at Qatar for both are about QR100 difference. For the standard S5 is currently price at QR2375 and the Duos are now priced at QR2499 with free Samsung original S5 flip wallet. That itself cost QR199.
So I went to check it out and here is the picture I got.
By the way the local authorized distributor also sell older model S3. I did askes the price for comparison or for your reference, it is QR100.