Some of you may know that I submitted a question a while ago about custom formatting of fields. I know a number of other people have asked similar questions, so I hope this information will be most useful to everyone:
Thanks to Rob Fjerstad at Autodesk for providing me with a document regarding control codes and information on customization of the fields dialog box (the customization follows; I'll try to post the document as a reply, as it's not large, but makes this message too long.
I found out that you can directly edit the field format controls by opening for edit the XML file AcFields.fdc located in your C:\Document and Settings\<user>\Application Data\Autodesk\AutoCAD 2005\R16.1\enu\Support
I suggest you make a backup copy of this file just in case you need to restore it for some reason.
In your sample, if you search for Area down at line 698 you’ll see various formatting styles for the Object Area field strings. What I did as a sample was added the following in this section, at line 701:
<Format>
<DisplayName>My Area Format</DisplayName>
<FormatString>%lu2%ct4%qf1%PR0 S.F.</FormatString>
</Format>
When I then created a Object field with property Area I then had in the Format list my new entry called My Area Format at the top of the list. You could then deploy this updated AcFields.fdc file to the others AutoCAD seats in your company.