If you are looking for a big commission, Enric Torres-Prat is the artist I would recommend. Currently, he's working on my 4th commission, and none of them have disappointed. Painted commissions, large size (18"x24", 20x28, and larger options). Not cheap, but worth every penny. He has a gallery on CAF...most of the paintings feature women and/or wildlife (he's possibly best known for his work on early Vampirella covers), but there's a gallery of Tarzan paintings as well. Probably my favourite artist, top 3 at the least. Can't wait to see my Hela/Valkyrie finished commission!
Enric Torres-Prat's CAF gallery:
http://comicartfans.com/GalleryDetail.asp?GCat=25468