Never said I knew everything. What I said I knew I knew.
Nice PsoneP.
I have not built a zn-40 n64 portable. But neither have you. So far I have only seen a WIP. But thats all it is, A WIP and nothing more. However, I have finished 2 flawless, successful zn-45s. Which is, unlike your next statement, incredibly close. In fact....
If you call a inch an a half a little thicker! See for yourself.

Evidence:
http://www.polycase.com/category/size/e ... eries.html
Zn-45 = 2.363
Zn-40 = 1.675
Subtact the two to get: .688
I would hardly call that:
an inch an a half
The sizes are very close, enough to easily compare.
Yes, in a mockup, they do fit. however, only in a mockup. The cell sizes and amperage of my batteries and almost the same! Nice choice, I like those.
Onto the fans. Of course a fan of that size would fit, but what good would they do? Aside from wasting power circulating air through what is not an airtight case, I can see no benefit, unless your 3.3v stepdown gets super hot.
Anyways, a work in progress is not going to convince me. It is all still in theory, I could have showed you the same thing. A finished portable, however, would sucessfully prove that it can, and was done. Untill then, it stands possible in theory. You have proven that much, and I commend you!
Alright, I have made my points clear. I would like to see it finished, and if you are successful, congratz, welcome to the big leagues!
SS