This is not a management problem. This is a programmer problem. This data is obviously not displayable in the way this programmer is trying to display it. Excel can't even begin to handle that. Anyone that would even consider having a datagrid with 25000 columns, or even 2500 columns, or even 250 columns, is clearly not ready to be doing UI design. The requirement is NOT to have 25000 columns in a datagrid. The requirement is to give the user access to 25000 peices of heirarchically(sp?) related information. That is more like a treeview or a nested datagrid, or some other type of "drill-down" UI. Having said all that, if you were to actually try to implement this as a datagrid in a way that was fast enough to use, you would have to virtualize the datagrid so that it loads as the user scrolls, and unloads the portion that has scrolled off-screen.

Standard answer: It can be done in two weeks, provided nothing unexpected happens.