In the end, I decided to go with what I know and drew their names on some watercolour paper, coloured them in, then framed them. Here they are:
They were really easy to do, only took a short while, and so I'm also doing another for a fundraising page on FaceBook, called A Mile Of Rainbows - parents raising money to fund their daughter's physiotherapy - she has cerebral palsy. They are holding a fundraiser tonight at 8:00 pm UK time, and I've offered to draw a child's name as a prize. Check it out on FB!