Mailmerge into a single Word templated document - e.g. a "New Letter" function

This is essential feature for most professional services. You call up a client, you need to write to a letter to them, you should be able to click a button to open up a Word document with their name and address details already on the page. (Having to manually write it in again and again is very wasteful of time, and the data in bound in boxes so you can't even copy and past it in by hand - you have to write the whole name and address in manually with each and every letter -- which is slooooow and not as good as most other systems which already have the "New Letter" function.)