I just need some sort of reference on how to build a custom android device and I can take it from there.

Not trying to discourage you but it isn't as easy as you think.  If you want android check out http://forum.xda-developers.com/.  You can read those forums and you might learn a bit about the software side of android.  They don't seem to like noobs very much though.  Try soft modding roms for a phone or something.  I'm also pretty sure that there is an android project for the Raspberry Pi.  You can learn a lot from actually starting a project and finishing it.

Tests really aren't about getting an advantage, they're more for showing what you know and can produce on your own. Actually, one could argue that if you possess the knowhow to create such a calculator, you really wouldn't need it for those tests.

(Also, the tests are easy)

You know, I never took my SAT's :'(

Did you just take the ACT instead?

Good luck.

It's not cheating if you follow the rules, and the rules are very easy for math section.

First, I believe that the rules for the calculators are more of guidelines of what a logical person looking for a calculator should bring. I do not this that it is meant to find loopholes.
What I imagine, would happen is that you would go to the SAT, they would see your strange looking calculator, and they would either take it up, or more likely they would take a picture of your calculator, send it to a higher up administrator (and the people in the room would hate you for delaying the test) , and the higher up administrator would likely say that it was illegal. (That’s what happened when someone wore a t shirt with a periodic table to the AP Chemistry test)
Also, the SAT doesn’t need that good of a calculator. Also, if you make a new calculator, you would have to program all of the software.
Also, it is already very easy to cheat with a calculator, at least with my TI 83 and Ti Nspire, but I despise even the smallest cheating, so I deleted my Periodic Table before taking the chemistry test. (What I think would be nice would be if Omnimaga, and maybe TI Planet too, made it a rule to never, if any one finds ways, never post directions or files to cheat or disable Press to Test mode)

But, on the note of new calculators and ideas, I think an accelerometer, camera, and side buttons (like the iphone) would be awesome on a calculator

Also, if you make a new calculator, you would have to program all of the software.

That would be one of your biggest problems when making the calculator, it would take very much work to make it as good as a normal Casio or TI.

And yeah, Omnimaga deleted two programs to disable PTT and maybe also the posts saying how it worked.

Adding to that, SAT math really doesn't need a calculator. Calculator is only OPTIONAL in SAT math. Heck, I didn't even see the distance formula questions in there.

(What I think would be nice would be if Omnimaga, and maybe TI Planet too, made it a rule to never, if any one finds ways, never post directions or files to cheat or disable Press to Test mode)

That's what has been done on Omni for over a year already. I don't know for TI-Planet.

But yeah a new calc should not be made so that we can cheat on tests easily and it should have anti-cheating protections that can't be bypassed easily. Otherwise there's no chance it will be allowed in tests. Even some TI calcs are banned from certain tests