Alan Macdougall figured out how to use the blogroll macro to render links to his subscriptions, just like the ones that appear below my calendar at the right, by pointing at mySubscriptions.opml. I was saving this one to show people a little later, but now the cat’s out of the bag. 
As it turns out, there’s an even easier way than pointing at mySubscriptions.opml with the blogroll macro, which doesn’t involve finding and copying any URLs. Here’s how:
1) Update Radio.root.
2) Edit your home page template.
3) Add the following macro to the template, in the location where you want your subscription links to appear:
<%radio.macros.mySubscriptions ()%>
4) Click the Submit button.
Update 1:43 PM: Andy Fragen got this working. If you did too, leave a comment, and I’ll shoot you a link.