Reader Chris Sauve got an AppleScript book for Christmas and is off building neat and helpful things now. One of his first projects is a script for OmniFocus to defer start dates of tasks using the OmniFocus natural date syntax.
The script will initially ask if you want to automatically flag tasks while deferring them (which is the basis of my OmniFocus workflow), and will then present a dialog box for you to enter the amount of time to defer the task for. The syntax is the same as OmniFocus's: you can use "weeks", "w", "days", "d", and 24- or 12-hour time specifiers (with or without the AM/a/PM/p). So, for example, writing "2w 4d 12:40pm" would defer the start date of that task for two weeks, and four days, and would set the start time to 12:40pm. You can exclude any of the three pieces and it will still work (as long as you specify at least one item).
The script is inspired by Dan Byler's work and rather useful for those who rely on start dates to keep the amount of available tasks in OmniFocus at bay.