Are there any figures for its adoption in corporate environments? Does anyone know of large corporations that have adopted it for projects?
Not at all at conservative, Fortune 100, financial services companies.
Then again, software development in general is viewed as something distasteful that can't be outsourced fast enough to suit management.
British Sky Broadcasting is using Grails for their main web presence. See here a blog post of Graeme Rocher about it.
I know the federal reserve here in Minneapolis has used groovy internally on some projects, though to my knowledge they haven't used grails yet.
About to start a Grails project at a large media company in NYC.
Based on my experiences as a consultant, media companies are about a year ahead of typical corporate america.
Additionally G2One being acquired by SpringSource will increase the overall adoption of Groovy/Grails.
Wired.com grails usage case study
Also, apparently, grails is being widely used in Atlassian.
I've used it for a smaller financial services company, but in their public-facing website, not their backend operations.
Since it compiles down to WAR files for deployment, I suspect that it will have a gentler adoption path than completely out of band solutions like RoR. However, the current financial climate is probably going to put a severe crimp on any development projects, let alone ones that try and use newer, less proven technologies.
Very limited in the railroad industry. Nothing heavy, but a few things here and there. Unfortunate as they are all Java shops. They could really make some headway if they did use it.