One of the worst kept secrets about Leopard is now officially public knowledge: There’s no Classic environment.
Do Classic applications work with Mac OS X 10.5 or Intel-based Macs? Classic applications do not work on Intel processor-based Macs or with Mac OS X 10.5. Upgrade your Mac OS 9 applications to Mac OS X versions. Check with an application’s manufacturer for more information.
As a developer (even one without access to the seeds), this isn’t a surprise. The Leopard feature list reads like a list of things that Apple could do with Mac OS X if Classic wasn’t an issue. Three examples off the top of my head: Time Machine, Spaces, and resolution independence. It wouldn’t be Apple’s style at all to introduce a bunch of hacks into Mac OS X to make these things simply not work with Classic applications instead of being completely incompatible with the Classic layer, and they’re certainly not dusting off their Mac OS 9 development systems to code support into Classic.
I haven’t had Classic on my system for more than a year now, so I won’t miss it at all. For those really early programs, mini vMac will probably work. It’s the PowerPC applications that don’t have a great solution ((Yes, there’s SheepSaver. I don’t think of it as a great solution, though.)).
If you presently rely on a Classic application, you’ve got a tough decision to make.