There are many devices with J2ME support. Some of them are available only in North America, some - in Japan and South Korea, other - in Europe. If you want to know how fast your app will work on most devices you will need buy a world map and go to the long trip.
I wrote simple test suite for devices with J2ME support. Main idea of the test suite is to have results of running SAME tests on DIFFERENT devices. Fore more information please see http://www.dogada.com/javame/. Test suite is distributed under the GNU LGPL. Source code and last test results you can download from the above web page.
If you have a device with J2ME support please execute tests and send results to the firstname.lastname@example.org. I add it to the freely available list at the http://www.dogada.com/javame/.