Here's an interesting fact about me: I'm actually not all that good at memorising things. I can memorise cards and binary digits better than anyone else because I invented a cool system for doing so more efficiently, and have been using this system since 2003. On the other hand, the 'numbers' element of the Ben System (I'm officially calling it that now - people have stopped using the name so much, and I realise that I like it after all) is exactly the same as, if not worse than, the systems used by other people.
So I need to expand it. Turning four digits into one image is the way to go, I've known that for a long time but been nervous of trying to do it, thinking that it'd be too much. But now I'm pretty sure it has to be done, so I'm going to give it a try.
Consonant-vowel-consonant-vowel is too restrictive, so my current thinking is that each image will have a two-part name, the first part starting with one consonant-vowel combination, and the second with another. Thinking up all the images is going to be tricky; committing them to long-term memory is going to be even trickier. But I think it's within the bounds of possibility. I'll let you know how I get on.