HSI has its OEM version of 1GB Radeon HD 2900XT available for american market. The card is listed at newegg and HIS Hightech H290XT1GG4DVN-R Radeon HD 2900XT 1GB 512-bit GDDR4 PCI Express x16 VIVO Video Card – OEM costs $530 + $6.61 for three business day shipping.
HIS card works at 743MHz core and 2000MHz for 1GB of 512 bit DDR4 memory. Physically the card looks exactly the same as the 512 MB version but it comes in a OEM box but without Half Life 2 voucher.
You can get one here.