further reasons for the above build plan.

1. can be manufactured and assembled at differnt places
2. Easier to get into workshop/transport
3. Final truing is simple, a few spanners, a few cups of tea, and a bit of time.
4. it can be moved, if required, and is simple to true up again
5. It can be built very accurately with simple tools ( pillar drill, cutters and grinders and weilder ),
6. it will be a lot easyer to get a large but solid bed level to the x/y, possibly even have a replacable bed for different configurations,

Cons

1, it uses a lot more steel, but if you want you bed to hold a lot of weight, its not a loss
2. It takes time to make sure all your cut pieces are exactly teh right size, and to get your bolt patters accurate, but, accurate pattens could be printed from a standerd desktop printer, and overlaid,

i can not think of many more cons,

you will notice that i have not mentioned the gantry yet, its because am working on a very differnt type of design, but i need the frame built, to make the final tweeks, my Y is going to be more like a cartridge than a carriage. giving me much better force resitance in all dirrections. Again, for standard XYZ, this may seem overkill, but, if i want to build a turret on one of the Y sides, or strap a B/C head to the Z, then it makes sense, .

any opinions welcome