While Samsung is continuing to add laurels to its wreath with the success of its best-selling Galaxy S3 smartphone, rumors have been trickling in that the Korean company is working on the successor - the Galaxy S4. Even as the rumor mill continues to be on an overdrive, some designers have come up with concept designs for the Galaxy S4 Mini and the alleged Galaxy S4.

Whenever rumors surrounding a fabled device emerge, designers usually get to work on coming up with concept designs, their take on what the smartphone may look like.

We take a look at some of the futuristic designs that are in the offing, courtesy designers.

Galaxy S4

The grapevine has been abuzz with rumors that Samsung is working on the next iteration of its super successful Galaxy S3 smartphone, dubbed the Galaxy S4. The company is speculated to take the wraps off the smartphone in early 2013, possibly at the MWC.

With Samsung denying the conjectures, any information available regarding the specifications and features of the Galaxy S4 have been gleaned from rumors.

Designer Ben Ling has come up with a few designs for Samsung's 2013 Galaxy line-up, which include the Galaxy S4 and the Galaxy S4 Mini. Web site Concept Phones featured the two devices.

Ling's notion of the Galaxy S4 revolves around the rumored specifications and features. The concept Galaxy S4 sports a 5-inch AMOLED Plus full-HD display (1080p resolution). The concept smartphone is fueled by a 1.9GHz quad-core processor, has a 13-megapixel rear-facing camera and an 8-megapixel front-facing one (both have 16x zoom), and a 2500mAh battery. The concept phone also packs in Android 4.2 Jelly Bean, 2GB of RAM, NFC support, and 16/32/64GB on-board storage.

The concept Galaxy S4 is a little less rounded than the Galaxy S3, and is 0.36 inches thick.

Designer Nikolai Prettner too has come up with a concept device for the Galaxy S4 with TouchWiz 6, which will bring a redesigned version of TouchWiz to the Galaxy S4, and has an aluminum frame, plastic back, and a flexible plastic screen.

Prettner's concept phone has the Galaxy S4 featuring a 5.1-inch Super AMOLED Flexible display (1080p). The concept device has a 1.9GHz quad-core processor, a 12-megapixel rear-facing camera, a 4.5-megapixel front-facing HD camera, and 16/32/64GB on-board storage. The concept device supports wireless charging, LTE, HSPA+, and packs in a 2650mAh battery. Prettner's version runs on Android 5.0 Key Lime Pie and will have S Note, S Music, S Voice, and S Gestures. The concept phone weighs 3.60 ounces and is 0.30 inch thick.

Galaxy S4 Mini

Interestingly, no speculations surrounding the Galaxy S4 Mini have emerged yet, but a concept design phone for the same is still out. The Galaxy S3 Mini was announced in October this year and made it to the UK shelves in November. With the smaller sibling of the Galaxy S3 relatively new, it is early days yet for a successor. However, it seems concept designers have other ideas.

Designer Ben Ling also came up with a design for the Galaxy S4 Mini, which is "fresh and new", according to Concept Phones.

Ling's concept of the Galaxy S4 Mini has a 4.55-inch Super AMOLED TFT HD screen, a 1.5 GHz quad-core processor, a 13-megapixel rear-facing camera, an 8-megapixel front-facing camera, 2100mAh battery and Android 4.2 Jelly Bean. TouchWiz UI is also present and supports multitouch "with up to 10 fingers." The idea of an 8-megapixel front-facing camera for video chats seems a tad farfetched, but since it's a concept design anything goes.

While the concept devices may not exactly be ground-breaking in theory, their emergence is reflective of how popular Samsung smartphones are. When and if the Galaxy S4 and Galaxy S4 Mini make an appearance, it will be interesting to see how the concept devices match up to the original.