You may hate newspaper but all I will say is that it is the BEST substrate for your burm. So, if you have your snake's best interest in mind, newspaper is best.
But, since you are looking for something more "natural" looking, there are some options; all of which have their positives and negatives (the biggest concern with these is the possibility for ingestion which is something you will spend a great deal of energy in preventing). Substrates such as cypress mulch, cypress bark chips (some of the big hardware stores sell these really big "chips" of bark which look nice and are difficult to ingest because they are the size of a small softball), aspen bedding (not really natural looking but I have found that it works pretty well and looks okay), river rock gravel/pea gravel (once again, every time the snake defecates, you will need to empty a good deal of gravel out to disinfect and rinse it...it is heavy and not much fun to work with), sandy/soil substrate (actually, not a bad idea as it can be fairly easily scooped and raked to allow the natural microbes in the soil to break down the urates). There are undoubtedly outher good options but just thought I would share these as they may work for your purposes.
Rob Carmichael, Director/Curator
The Wildlife Discovery Center
City of Lake Forest Parks & Recreation (IL)