The PE-770 is the same as the 780 without the Disney patterns. It is still available. I bought a 770 a few years ago and have gotten a lot of use out of it. It has a port for a USB stick as well as a card slot. It also comes with several built-in designs, but they're a bit primitive.
The machine comes with two hoops, a 4 x 4 and a 5 x 7. Maximum is 5 x 7 however you can get a repositional 5 x 10 hoop for it, but that's extra.
I just bought a new Singer SEQS-6000 which has a 6 x 10 hoop, but it doesn't have an automatic thread cutter like the PE-770 has.