An interesting problem and one I've given some thought to lately as I've been doing a little MySQL work. I think the only way to build a good cross platform act is to work inside the limits of common boundaries (if your resources are limited). In this sense, you'd just drop the owner name from the query, but ensure all objects are owned by DBO.
The next best effort would be to implement branching items in your code, perhaps even in some "pre-compiler" that parses your code to make the appropriate changes for the platform. Some really neat technologies (Alpha Win32 platform, MS JVM, .NET) implement this. They make changes based on the underlying environment. Of course, this takes more resources than the first solution, but should provide better performance per platform.
The last solution requires more resources and isn't worth it IMHO, and that is maintaining two (or more) codebases.
Steve Jones
steve@dkranch.net