Having helped assemble a water-jet cutter that was used for cutting headliners for cars, I seriously doubt you could make a desktop version as just the bath depth required to absorb the stream makes that a non starter. Back to the original question of laser cutting 10mm thick acrylic, I would go with milling as the power of the laser would have to be strong enough to not only cut the acrylic but also resist the tendency of acrylic to transmit light along and across its structure. I have seen laser etching into acrylic and that works but has limits as well.

What are you using the acrylic for?
Is there another plastic that will do the job and be easier to work?
Is the possible production level high enough to offset the cost of the laser and the cooling equipment needed?
If you are looking for finished edges, is milling the item then having it flame polished by an out source or buying a unit to do that reasonable to cost?

Those are just some questions that came to mind about where you are in this project and things that you might want to look into.

Michael