Sadly, SeedManager isn't going to see much in the way of updates for a bit longer, because my laptop needs replacement. It BSOD's if I try to start Minecraft or anything else with 3D graphics. I could write code all I like, but I'd need Narc to test for me, and his time is less open than it used to be. We'll definitely get out a version for MC1.5, once that's possible, but actual progress is probably going to be nonexistent.
If anyone wants to help, give me your GitHub username and I'll add you to the project. Or, if you'd rather, you could always take the license at its word and go make your own fork. I'd strongly appreciate it if you keep your additions under the same license, but MIT licensing doesn't require that.