A new tool launched yesterday, and it promises to make it easier to create Kindle eBooks.
Kindle Writer, a product of Tekline Publishing, is designed to support all the stages of making a Kindle ebook. This app is similar in function to Sigil, an open source Epub editor, but it does a lot more. It has several stages including editing the original text file, adding formatting, and it even can assist you in uploading the finished ebook to your KDP account with Amazon.
I have not had a chance to test it yet. The app launched yesterday, but the trial version available yesterday did not let you make eBooks. A new version was released this morning which removed the block.
Kindle Writer is available as a 30 day trial, with a retail of £25.