the best and easiest way to print on leather is to use pictaleather. it's a new leather printing solution that uses sublimation transfer. you can print on a range of existing products using a standard flat bed heat press, the products are available blanks and ready to sublimate. If you can't find the product you want within the existing range a blanks A3 sheet is also available. for users without an heat press they also print various leather products on demand.
Hope this helps