Mahjongg Towers - description from Softdepia.com:
Mahjongg solitaire as you never seen it before. Play traditional 144 tile layouts or step up to the 'towers', with up to 432 tiles and up to 9 level deep. Mahjongg Towers will keep the best Mahjongg masters busy for months. With game play variety ranging from quick 80 tile diversions to grand master towers that keep you clicking for up to an hour on a single layout. Includes an easy to use board editor to create custom tile layouts. Once a board is created there is an option that allows your creation to be shared with players around the world, resulting in limitless gameplay variety. If you tire of the 24 boards included with the game, click a single button and instantly have access to as many as 150 new layouts created by Mahjongg Master from around the world. Awarded a five cow rating out of five from Tucows shareware site.
Mahjongg Towers is a "Free to try" program. You can download and try it for an evaluation period.