>In American Sign Langauge, there is a popular and wide-spread form of visual poetry called the ABC Story<

Brandon, I think I get what you mean. The words of line 1are made with the A handshape, the words of line 2 with the B handshape and so on? So the English equivalent woudl be the words of line 1 beginning with A, those of line 2 beginning with B etc?

Or just the first word / sign of each line?

I don't know a word for this kind of poetry. It also reminds me of rebus or acrostic poems, where the first letters of the lines, read downwards, spell out a word or phrase. No idea what that's called either, nor can I find an example. I seem to recall there's one somewhere in Vikram Seth's 'A Suitable Boy', but this is another book that has checked out of my bookshelves without formal permission....