Yup, finding a used one should be feasible. Although, I'm not giving up my 04 with an NV5600 any time soon. I bought mine new off the dealership lot, and got it for below dealer invoice because it sat there so long without anyone buying it. Fleet manager I bought it from said it sat there for almost a year before I bought it, mostly because it was a 6 spd and molten red, which was a combo that didn't sell great. I snagged it up for a great price, and love my truck. It may take some searching, but you'll find one out there.
I've got the same, a 07 5.9 6 speed. When I sell mine it will bring a premium. Funny thing is, in 07 I bought it brand new off ebay with 1 click. Window sticker, $41K, I spent $31.7K!!!! Been the best vehicle I've ever owned.
1988 Chevy CC 5.9 12v swap, baby "earth roamer"
DSM had bookoo ST manuals on their lots,but I wanted power seats,and you couldn't get them without going to an SLT. Special ordered and it arrived up there in 29 days. Mine listed for just under $40K and went for $30,700+$750 freight down here. A guy from O'side and I received ours for Christmas '06.
My friend got his '07 2500 ST regcab G-56,4wd,LSD,cruise,a/c,forged aluminums and 285-70-17 Toyo's for just over $27K from DSM. He flew up and drove it down. It's survived probably a dozen runs down to the Baja Pacific northwest coast with no issues.
I can't imagine selling mine.
2007 Dodge 2500 Regcab 4wd 5.9 CTD. G-56 , TC800 Northstar popup 24/7.