Sure you can. 

To be fair to GridMonger, its ability to almost instantly provide you with an edit/insert interface to your data is very powerful and in many cases will suit your users just fine.  Plus, custom code templates can now fire before and after an insert or update if you choose (introduced in v4.80), which is extremely powerful.  And beginning in v4.70 two levels of separator bars were added to help break up and logically organize large forms.  

But if you want to go the extra mile, especially with respect to layout, its easy to do while still retaining the core feature set that makes GridMonger indispensible in the first place:  The ready-in-20-minutes GRID stuff.

If you want maximum flexibility, try this config out for size:

1. Set up your grid as Type M2 (LocalGrid.EditMode="M2";) which means multi-line editing is enabled, with multi-line delete but not multi-line insert.
    
2. Make selected fields in this grid editable.  This will give you a single- and multi-line quick-edit capability of these selected fields.  Great for quickee status changes, for example.
    
3. Use GridMonger's custom external link feature to call the custom editor of your choice.  This will be your custom record editor.  The edit function in Item 2 gives quick-edit of selected fields, and your own custom editor gives an expanded view of all data, the ability to edit that data, and whatever fancy layout and processing you see fit to put in.
    
4. Shut off GridMonger's ability to add records (LocalGrid.AllowAdd="";).
    
5. Put in your own Add Record link somewhere onscreen.  I like to put mine in centered bold text above the grid.  This link goes to the custom insert form of your choice, where again you can provide all of the fancy layout and processing you please.