Long ago, there was a thread about colsole modifications. At the time, I hadn't seen this site. So, I figure'd I'd share it with you guys:
http://devcast.dcemulation.com/There are some really cool tutorials on there, such as how to get an NES controller to work with your Dreamcast, and also how to properly paint the DC casing. Judging by the pictures, I think the guy has also made Saturn, PSX, and arcade stick controllers for use with Dreamcast.
There are also some neat pictures there, and apparently he is going to be adding tutorials on how to make a homemade DDR mat and homemade Coder's Cable up soon.
Anyone seen any other cool console mods? Comments on these or the site posted?