I???????R is defined in Chambers as 'someone who designs and creates a new and imaginative product, or piece of technology (originally a person doing such work at a Disney theme park).' It's been around for quite a while!
Thanks Jazzgirl and Malone. I'd never heard of it (and I've been around for quite a while too!) but Word Solver should have. It has now enabled me to get 19 across and 20 Down (which I love!) and 26 Across in a rush. Nearly there.