
By chance I happened to read today an interview with the principle author of sketch/skencil, Bernhard Herzog. He said that his paid work was with http://www.intevation.net/, who among other things work on http://freegis.org/. Please have a look at that site: it contains many tools. You might consider using skencil (http://www.nongnu.org/skencil/, or the more memorable http://www.skencil.org/) instead of inkscape for your work, especially if you're willing to pay Intevation for Bernhard to customize skencil for your needs. In any case, skencil has better support for user extensions than Inkscape at present if you want to work in-house. Skencil is written mostly in python, which facilitates writing customization in python (an excellent language for small jobs like scripting). I notice that http://www.nongnu.org/skencil/addon.html includes a plugin written by the aforementioned Intevation.
To my knowledge, skencil has no support for "glue", btw.
Inviting you to look at freegis.org and skencil should in no way be taken as dissuading you from using Inkscape: as I mentioned privately, we at Monash would be interested in hearing what you're doing and whether it's appropriate for us to work in that area (in which case we'd be more interested in using Inkscape than Skencil). I mention skencil and freegis.org only in the hope of finding the best tool for the job.
pjrm.