I think if you could hit two studs with every cabinet you would be ok as the shear load of the cross piece is being transfered into the studs anyway.
The reason for the nailing blocking between the studs is that you will rarely have the cabinet fall perfect on two studs IE a15 or 18" wide cabinet would fall on two studs that are 16 on center fine but the one next to it would have nothing to grab to.
The easiest is to cut out and insert the nailing blocking or to nail a 1 by 4 ontop of the wall both at the top and bottom behind where the cabinets will be and secure it into the studs and then secure the cabinets into the 1 by 4. I noticed them doing this in Atlanta where everyone was using IKEA cabinets. You have to be careful that the ends of the 1 by 4 fall on a stud. (no IKEA in central FLA boo hoo, their system uses a metal rail to hang the cabs so problem solved)
If you went this route you would have to have deeper cover panels on the end and or put trim around to cover the 3/4 inch gap.
We move and remodel alot can you tell
