I was looking for high resolution versions of the SegaNet and MIL-CD logos recently and wasn't able to find any, so I decided to fix that by making my own! I'm no Photoshop expert (in fact I made these in the free Paint.NET) but I think they came out quite nice. Feel free to use these if you need them for anything.
Credit for the SegaNet font goes to whoever created the fonts here. There are fonts for a ton of other Sega-related things there as well. Oddly the Dreamcast font isn't among them.