MetroPCS might not be in the exact same league as Verizon, AT&T, Sprint or T-Mobile, but the regional carrier has grown steadily in the last couple of years, attracting more and more customers. Based on a leaked roadmap, however, it seems like we ain’t seen nothing yet, and MetroPCS might be looking to seriously step it up by the end of the year.

The carrier is planning to add no less than eight new smartphones to its portfolio in 2012, if the leak’s source proves accurate, and the leading name on the list is by far the Samsung Galaxy S3. Already up for sale from five US carriers (Verizon, AT&T, Sprint, T-Mobile and US Cellular), the S3 should hit MetroPCS “after September and before December”. That’s certainly vague, but at least we know that soon enough Sammy’s flagship will reach even more users.

The Galaxy S3 is not the only name that drew our attention on MetroPCS’ supposed launch schedule, with two other Samsung phones, two Huawei devices, a ZTE, an LG, and a “Coolpad” (?) all battling it out for the headlines.

Samsung’s Galaxy S Lightray 4G is the first of the bunch to arrive, with its launch scheduled on August 8, which is one short week away. We talked about the Lightray a few days ago, and about how it could come with a 4.3-inch Super AMOLED Plus display, a 1.3 GHz processor, an 8 MP rear-facing camera, and Android 2.3 Gingerbread.

Two weeks after the Lightray, something called the Coolpad Quattro 4G might hit MetroPCS. This has had a photo leaked already (below), and, according to rumors, will come with a 4-inch WVGA display, a 1 GHz processor, 3MP camera, 512 MB of internal storage, and Android 2.3.

August 29 seems like the most crowded date in MetroPCS’ summer schedule, with both the LG Motion 4G and ZTE Anthem ready to hit the market. The Motion has made a short photo appearance earlier this month and should come with a Snapdragon S4 processor, a qHD screen, 5 MP camera, and pre-installed Ice Cream Sandwich. As far as the Anthem goes, that is a huge unknown for the time being, but hopefully it will be a part of ZTE’s plans to foray into the high-end market niche.

The Huawei Pinnacle 2 and Samsung Contour 2 are scheduled to be launched in early and mid-September respectively, and there’s also not much we can tell you about them. It’s obvious that both will be rehashed versions of older phones and it’s also very likely they’ll be low-end devices, but their exact spec sheets are a complete mystery.

Finally, the Huawei Verge is the only device appearing on the leaked roadmap without any approximate ETA, but, as it’s placed before the Galaxy S3, our guess is it’ll come sometime in October. All of its technical details are kept under wraps, but we surely hope, like in ZTE’s case, to see a device closer to the high-end Ascend line than the entry-level M735 or M835.

That’s it, folks, these are MetroPCS’ complete plans for the end of 2012. What do you make of them? Could the new phones take the carrier towards new heights? Did any of the eight devices especially draw your attention? Which one?