Poker would be a good start, and it has pretty much everything you required. Unless you want to make a custom keyboard, then you will need PCB, case, key caps and your selection of switches; however, at this point it seems you'd be better with a stock keyboard.
For the arrows, I'd suggest you to take a look at the Space-Fn concept that may be implemented in many ways, it makes dedicated arrows pretty much unnecessary. I use to be one of those that just cannot live without dedicated arrows, I spent so much time looking at weird layouts to fit them in a sixty, until I gave Space-Fn a try, and now, I am very happy with an almost standard 60% keyboard.
Good luck.