I have finally broken the back of the modelling required to templates work cleanly. The latest drafts are at:
- archetype model: http://www.openehr.org/svn/specification/TRUNK/publishing/architecture/am/aom1.5.pdf
- template model: http://www.openehr.org/svn/specification/TRUNK/publishing/architecture/am/tom.pdf
Note - these are undergoing heavy editing. However, the AOM constraint model is fairly close to complete I think. it includes changes to support templating.
The TOM you will see is minimal - one of my original goals; the text is still undergoing a lot of change.
I will post regular updates in the remainder of the year, leading to pretty good quality documents sometime in the next month or so. So if you are not burning to read this now, you can always wait a few days 
- thomas beale