Hi rob
as for the dry ice blasting I have no experience just Googled it and it sounds just as messy
from Wikipedia
Dry ice-blasting is a form of abrasive blasting, where dry ice, the solid form of carbon dioxide, is accelerated in a pressurized air stream and directed at a surface in order to clean it.
The method is similar to other forms of abrasive blasting such as sand blasting, plastic bead blasting, or sodablasting but substitutes dry ice as the blasting medium.[1] Dry-ice blasting leaves no chemical residue as dry ice sublimates at room temperature.
that blasting really is a messy business. but it does pay well. as for the cfm my uncle has a 180 cfm that is used for lighter mobile stuff like oak beams barns ect he had it all mounted on a trailer like the farrow system but de-mounted it all as he finds it easier to have the pot hose media ect in the van and just tow the compressor.
have a look at the quill falcon system thats a wet and dry unit.