Mine was an R4, but I've heard of the Supercard. I don't remember the ARM7 patch but I've heard of it.

I do remember trimming games. The DS "Nitro" card held 32MB of storage, and every ROM was 32MB, even if the game didn't take up that much space. A trimmer would remove the junk data. Some games, for anti-piracy purposes, would detect the junk data, so you couldn't trim them. (If a game was less than 16MB, or 8MB, it would go on a 16MB or 8MB card, respectively; I don't think there were 64MB cards, but there might have been.)