I got mine from a local shop after searching many shops to find a US 3DS XL package since most of the 3DS XL packages here are Middle East versions which their serial numbers starts with "SS". Unfortunately I couldn't find any information regarding the middle east serial numbers in here nor in any other forums, so I just couldn't take the risk of purchasing one without making sure that the one I'll buy has the firmware I seek. Luckily, I found a local shop that sells the US 3DS XL package, I looked at the serial number, and it starts with SW1232XXXX! The number is so damn close to SW1231XXXX which was reported by someone here that it has a version 6.1.0! So I asked the seller to gave me another package, but he said this is the last piece and the rest of 3DS XL packages are Middle East versions. XD
So what are the chances this will be 6.1.0? Maybe that guy who reported 6.1.0 was lying or maybe he got a used one. But then again, I'm limited of choices so I took the risk of purchasing it. I even couldn't wait to return home to check its firmware. I unboxed it right way after purchase, turned it on, system settings, and ... it is version 4.4.0-10U!
Side note: Generally, Middle East follow the PAL region, but in this case, we saw that all Nintendo products follow the NTSC/U region. I don't have a sure answer but maybe because we don't have an official distributor.
tl;dr
Blue/Black 3DS XL
SW1232XXXX
Ver. 4.4.0-10U