I'm gonna go out on a limb and say they'd be definitely cheaper.
I am not sure they would be much cheaper. Your talking big and expensive pieces of aluminum, plus mucho machining time. A 1" sheet for 1 60" x8" board would cost about $300 I bet, that's before you touched it with a machine.
A 1" x 10" by 72" slab is about $400, (that's what it would take to get a 1st gen C2 dagger out of it.), if you're buying it retail. Which who the hell buys anything retail. Probably be cheaper if you're getting it in a 20' stick too, and you'd be able to recoup a small percentage recycling the waste.
I'm curious what the machining would cost, or more importantly how long it would take. If the machine is $100/hr, would it take six hours to do it? I kinda doubt it in a CNC, and that's what it'd take to get it up to the cost of a C2 dagger board.
I like these discussions. Way more than WtheF are we going to do with the Alter Cup.