Any tips on what sort of machine I should go for in terms of laser cutting?
Given the large cutting area, you need to have a higher power module for the cutting. For the Lowrider, the highest power module I’ve seen used on the forum is the LaserTree (40W) module, though I see they now have a 60W module.
As for an existing engraving setup, the largest working area I’ve seen is on the AtomStack X70 with a working area of 800mm x 850mm. It claims 70W of output (optical) power, but I’ve not seen any independent verification of this output. I know someone with the 40w version of this machine, and he is happy. The cost is $1850, though AtomStack seems to have regular discount sales.