Sounds like a really unique choice. Im afraid Im with the others though, and wouldnt think that velvet and gauzey fabrics would withstand the washing required for a baby quilt.
However I reckon you could get leafy or wooden patterned cotton fabric fairly easily, and some printed cotton fabrics do almost look textures, and so would be a good replacement for the velvet. Then to make the LOTR theme have you considered using the fabric stuff that you can print your own pictures on? Im sure there are plenty of pictures or whatever that you could print out, and I understand (though someone might correct me) that it would probably wash a lot better.
Whatever you decide I certainly hope you post a picture when your done!