Using Japanese Arrows X on At&t prepaid plan, is that possible?

Hello, I have looked on Google for answers, but I just cannot find the complete answer.
My HTC EVO Shift is getting kind of old, and after HTC decided to give up on Android updates, I decided that I should upgrade my phone.
I looked around to find the best phone in both looks and specs, and I found the Arrows X by Fujitsu to be a great phone to try. I was on a vacation to Japan and was able to try the phone out.
The only problem is that obviously, I will use the phone in the USA, so the phone needs to be at least somewhat useable with an American carrier, preferrably 3G, maybe even 4G.
I have read that it is possible to use NTT Docomo carrier phones in America with At&t because both are GSM networks and their signal frequencies are compatible. However, I do not want to spend too much on my phone each month.
So, my questions are:
1. Is the phone I want (Fujitsu Arrows X f-10d for NTT Docomo) possible to use in America?
2. What can I do if I use the phone in America? (3G, 4G, or both?)
3. Is there any way to get the phone on At&t's prepaid plans with 3G and/or 4G in a legit way?

Thanks,
SarcaGuy

EDIT:
Is there at least any phone in japan compatible with at least one carrier in America?

 

Uh... any tips?
I am sorry for double-posting, but I need an answer quick so I can buy the phone in Japan before I go back to the USA in a couple of days...

 

Please, someone, will you tell me if there is a way to use Japanese smartphones in America?

 

Thanks!
I just gotta find the unlocked version cheap enough online.
Only if NTT Docomo allowed SIM unlock codes to be bought online...

Edit:
Cutting the SIM card to be the same size as a FOMA card seems to be the hardest challenge, I might cut straight through all the flash memory of the SIM card on my first try...