If you're willing to pay, Transcend (and possibly others) makes 4GB SD cards at various speeds (about twice the price, but may be worth to you instead of changing camera). These are not compatible with all devices, though.
These cards have been tested with other CANONs (older A6xx, S3, etc.) and are a 90% sure bet.
Note that these must be formatted to FAT16 for CHDK to boot, of course.