OK, I've had some time and have come up with three options:
Option 1: Typical Modal Dialog Box
The user would select a layer to transfer the Object to, the Dialog would close with the user proceeding to next select the object(s).
Option 2: Modeless Dialog Box
This Dialog Box would remain "Open" allowing the user to run the command on multiple objects. Select a layer in the list box and then picking the "Select Object" button the focus would be shifted to the drawing space to, well, select an object(s).
Option 3: Popup Modeless Form
This very simple form would "pop-up" at the cursor location. This would make a good toolbar button. Once double-clicking on a layer, the form hides, and the focus is back to the drawing to select an object(s). If the user decides to cancel the command, once the mouse leaves the form it hides.
All forms allow resizing and the last layer selected would be saved to the blackboard to be selected the next time the form is shown. The modal form is the easiest to impliment with something like (setq layerName(KWIP:SelectLayerForm)). The modeless forms will take a little bit more coding, and may need to be the main calling function (command). I'm experimenting with that now.
The Help System: if you guys want to go HTML (that's what I use) I can provide a simple modeless OpenDCL dialog that displays HTML pages.
jb