Found a way to read .mobile files without changing file name. Just get the drop box app on your kindle. Use the webbased or computer app to add your .mobile files to your personal drop box account. Then go back to the kindle click on the file in drop box and it will open in the included drop box doc reader. It has great features like txt to speech, txt color changer for dark reading, percentage read, and book mark. Also works with .pdf .doc .odt file types you can also create edit and save word docs which can be easily shared. Works great for reading groups because they can share one file across many devices. Check it out
www.dropbox.com