standard SDHC card sizes?
 

I'm imaging an 8GB SDHC card and I was wondering if there's any SD standard regarding the number of blocks for each size card. I checked www.sdcard.org but didn't see anything in the public area. blockdev --getsz /dev/mmcblk0 for my particular card is 15954944 and I'm wondering if this image would be feasible for any other 8GB card. This is a SanDisk Extreme III card. I don't own any others, otherwise I'd check. If anything this should be safe for cards with a few more blocks, but not less. I'd considered partitioning it so that only 7.9GB were used, then imaging only that size so the image would fit on pretty much any 8GB card (the file system it contains only takes up about 5GB, but the empty space is meant to be used.) Thanks.
Kevin Barry