I am lucky enough to be doing a job that I truly love. Illustrating for children's books. Some of these I also write. My goal has always been to create a beautiful work of art that children can hold in their hands, take to bed, take outdoors, take on vacation, and when they feel they are too old for that 'sort of stuff', place on their bookshelf to be discovered much later in their lives.
E books are something new. Six of my 30 + books have been converted into E-books, and I am sure there will be more conversions as the clients I work with want to cover the children's market from all angles.
My personal preference is the hardcover book. With or without a dust jacket, (they often get lost or torn) this is the book a child can hold, keep for ages, and pass down to younger siblings or their own children is still a timeless treasure. My own copy of Babar the elephant is on my current bookshelf. It shows the loving wear of the 50 years I have owned it. The marks of my children are there as well and when my oldest child felt she could give it up, she returned it to me for safekeeping. Most likely I will someday part with it again for a grandchild or two.
If you are planning to publish by seeking out an established children's trade book publisher who will acquire your manuscript or accept your illustration style for future books, you need to be ready for the long wait, the rejections, the disappointments, and the frustration. But if you persevere, there is a very good chance that your work will be picked up by a publishing house that not only creates a beautiful book, but pays you a decent advance and royalties.
If you plan to follow the shorter path and publish yourself, choose wisely. There are many publishing venues that promise a great deal and deliver less than you would expect. There are a very few that actually hold your hand along the way, help you create a beautiful book and offer you the additional option of creating an E book along with your hardcover or softcover book.
Check out the options offered by Create Space, Gorham Printing, and Ingram Spark. They all offer short runs, or print on demand and there is the option for conversion to an E-book if you wish.
There are different models here but one might fit your publishing needs. There are many good Asian printing houses as well, but there the minimum order for books is 1000, and then you have the problem of the language difficulties, shipping, and marketing and selling your boxes and boxes of books.