The safest way to back up own work would be to build and script offline. It would also help with the grid load, and allow residents to work completely undisturbed and unaffected by server lag.
Would it be possible to program a "light" version of the client, as a standalone software with the ability to use all building (aside from texturing) tools? Perhaps with an LSL interpreter to allow scripting as well. An official Linden Lab tool, exporting complete scripted linksets in a file format that can be uploaded (for L$10 perhaps, just like textures, sound files or animations).