Currently, the certification that gives the option of using Ubuntu for the test is the Linux Foundation Certified SysAdmin (LFCS) which gives the user the option of CentOS, openSUSE and Ubuntu. In the case of Ubuntu, it uses the latest LTS which is 14.04.
The test is very complete but you can get a bit of basic training using the EDX LFS101x: Linux Foundation Introduction to Linux Course which, for a limited time only, if you finish the course and pass the final exam, it gives a 100$ coupon for the LFCS course.
Another way of gaining the 100$ is in the following Ubuntu-news-team Mailing List post which mentions a 100$ bonus off the LFCS for all Ubuntu lovers:
$100 off Linux Foundation Certification for Ubuntu Members
This are of course focused or give the option of using Ubuntu as the base OS. Other exams like the LPIC of CompTIA+ are more general when it comes to which distro to use.