ANYWAY...
To re-state the point of all this:
Currently, construction, especially for large structures, is a huge pain in the ass. The biggest offender is the interface where you start with a 1 tile construction, then resize it with H, K, U, M. There is a rather small max limit to this interface, further compounding the problem, because when you put down the next section, it again requires resizing.
So, the basic suggestion is:
Allow the 'corner' method of size designation. Select one corner, select the other corner. Rectangle, square, whatever, it all works the same. No size limit.
Another issue with construction is material designation. Currently materials are sorted by distance, and must actually be available at the time you specify the construction. You must select a material for each block of the construction. Fortunately (in most cases), the list does not re-sort itself within the same construction designation. However, due to the fact that the list will be sorted differently for each construction, a macro cannot be used, because it will only select from the same position on the list every time, and not necessarily the same material.
Simply allowing construction without size restraints would take most of the pain out of this. You still need to hit enter once for each block, but at least if you designate a long section of wall, or a big floor, you can easily continue selecting the material you want, once you find it in the list the first time.
A nice feature (unlikely though) would be options like: Use closest stone, use closest block, which only need to be selected once for the whole construction.
Being able to set a construction to take from a stockpile (or the other way around) would also work.
Now, maybe this idea is a coding nightmare. However, it seems to me that at least the first part (designation of construction in the standard, corner selecting way) isn't that difficult, since that interface already exists, and could then simply feed the resulting rectangle into the existing material selection dialog.
In my mind, this is a small change that would have a big impact, especially for players who like to make large constructions.