Via Nokia Conversations in China, we hear that two new '4G' Lumia 630 variants the 636 and 638 have been announced, for the Chinese market. Details are somewhat sketchy, with only a Chinese translation to go on, so it's not entirely clear what the differences are between them. Both do have 1GB RAM though, rather than the 512MB in the international 630, presumably to cope with the demands of the richer character sets, though the extra RAM should help with bigger games.

A machine translation(!) of the page gives:

Today, Lumia family's first TD-LTE 4G phones - Lumia 638 official visit in China it. She not only continued the high-end Lumia series models with excellent industrial design dazzling colors, is by virtue of Microsoft's innovative operating experience with China Mobile advanced 4G network for everyone to bring a highly cost-effective 4G speed network experience.

If you want to experience the Lumia 638 advance brings super speed and super-convenient, then do not miss the start, held in Shanghai today Asia's top mobile event - Mobile Asia Expo (GSMA), Lumia 638 will be accompanied by Chinese LTE 4G mobile network stunning debut Oh.

Lumia 638 will be effective from June 21 officially on sale through all channels, the retail price of 1,299 yuan. Meanwhile, we also provide consumers with a richer 4G choice - equipped with China Unicom's Lumia 636 4G networks will also be on July 5 by the United States offering exclusive channels, the retail price of 1,299 yuan.

Tech details from the rest of the page include:

With quad-core Qualcomm Snapdragon processor with 1G RAM, with smooth Windows Phone 8.1 operating system, faster, lower power consumption, so you can enjoy a smart operating experience to fill the gap.

 

Lumia 638/636
Operating system	Windows Phone 8.1
Display	4.5 inches display full fit, Wyatt screen LCD screen technology, Gorilla Glass screen 3
Battery capacity	1830 mA
Network	LTE 100Mbps/50Mbps, HSPA + 42Mbps (Dual Carrier) / 5.76Mbps, HSPA + 21Mbps/5.76Mbps, Wi-Fi (b / g / n), BT 4, micro-USB
Processor	1.2GHz quad-core Qualcomm Snapdragon 400
Camera	5 megapixel autofocus
Storage	1GB RAM, 8GB eMMC plus 128GB micro SD card support for expansion

There's a decent smattering of local Chinese applications preloaded, from what we can make out, as you'd expect. It's also unlikely that you or I will ever get our hands on the device, but here's a photo of it/them anyway: