Hi,
you can do several things.
1. Contact one of the official LimeSurvey partners
[url]
www.limesurvey.com/
[/url]
2. File a feature request
[url]
community.limesurvey.org/bug-tracker/
[/url]
The same credentials as here in the forum.
Select in the upper right corner "Feature request"
If you offer a donation, there might be a chance that this will be implemented someday.
3. Do it by yourself.
Here a rough idea:
Data are saved each time the submit button is clicked.
On the first page capture the time and calculate the "end time"
On each page insert a script to show the count down
An example
[url]
www.w3schools.com/howto/howto_js_countdown.asp
[/url]
After the end time is reached you may
a. display youtr message and hide the submit button
b. display a message and clicking the submit-button skips all following questions
Joffm