Dreamcast PC - Help me design it!

I'm in the planning stages of a new project I have right now to build a mini PC inside a Dreamcast. I'm basing the build off of a AMD E-350 APU and I have some big plans for this but I would like some input from the community.

I decided to start this project because we have all seen PCs inside a NES, SNES, or other console case, but I have never seen a Dreamcast one. Why? Because the Dreamcast shell is the smallest of them all. This thing is really small, but I've already got some great ideas on how I can make it work.

My ultimate goal is to end up with a CLEAN and COOL build, something many have failed to do with even bigger shells such as the previously mentioned SNES PC. The design of the original Dreamcast gives a perfect space at the top of the system where you would normally put a disc for a large fan of some size. (Haven't measured yet.) This idea is a must and I doubt you can change my mind on this, it will add a big boost in cooling to the whole board.

Now I need help making some decisions. What should replace the controller ports at the front of the console? DVD drive is out of the question as the case is way to small to fit that but should I put a USB hub there or something?

Also how should I boot this thing? Should I save space and make life easier by just booting and saving all my files and running my programs all off of a USB flash drive? Fitting an SSD would be quite the challenge and I don't want an HDD because I wan't as little movement as possible inside the case. I want this to be a super clean build in the end.

Lastly what about a PSU? I could go with an internal Pico PSU, but if any of you know of a low wattage cheap external PSU that has molex among other necessary cables please let me know.

Thanks!