Yeah, for sure. I mean, I haven't tried it, but everything is configurable, so it should be. Spritesheets are defined in ShadowOfTheWyrm.xml in the <Spritesheets> element.
The size of the tiles is defined in swyrm.ini. Check out display_tile_size if you want to do something other than the defaults. If you want to do a tile size other than 16x24, you'll also need to supply a new font file, too. These are all configurable, so _should_ be okay to change, but I've only really tested in the one size, so it's entirely possible there may be bugs here, too.