I installed Hardy Heron alpha 5 in a VM and Miro doesn't compile on it. Amongst other things, Hardy uses Firefox 3, so it's likely we'll have to make some code changes to account for that. I only spent 20 minutes with Hardy and Miro to see where things are at--no clue how much work is going to be involved.
I'd love to get someone(s) to help with working out the issues with Miro on Hardy before Hardy releases. If you're interested in helping, leave a comment here, send me an email, or find me on IRC.
If no one helps out, then I'll probably deal with supporting Hardy after Hardy is released.