Here's a simple patch for $SUBJECT. It will remove any leading spaces from the grid cell display and replace them with '[...] '. In edit mode, the data is unchanged.
The only downside I can see to this is that the tooltip will show the modified data when it probably should actually show the un-modified data. Unfortunately that's handled by a SlickGrid plugin, which would have to be vendorised and modified (perhaps non-trivially). I don't think that's a big issue though.
