I'm wondering if there is any interest in having/developing spatial extensions for Derby?  I can see value in having Derby available as an embedded database for working with large spatial datasets.
I expect that adding spatial to Derby would involve:
- defining spatial types
- implementing a spatial index (probably an R-tree)
- adding spatial query and manipulation functions
As the developer of the JTS Topology Suite API, I would be happy to offer this package as a component of a spatial implementation in Derby.  Feel free to contact me if this is of interest.
Martin Davis, Senior Technical Architect
Vivid Solutions Inc.      www.vividsolutions.com
Suite #1A-2328 Government Street Victoria, B.C. V8T 5G5
Phone: (250) 385 6040 - Local 308 Fax: (250) 385 6046