I needed a quick fix for this so I tried a hack workaround. I added a bit of javascript to the resource file for the page that manages the file size loacted at: \desktopmodules\Smart-Thinker -UserProfile\App_LocalResources\Settings.ascx.resx. If you add the javascript to the localization code for 'Resource Name:plrblShowAudit.Text', when the settings page loads for the module the javascript will change the max length of the field from 3 to 4 and allow you to set a larger limit. I used 'Resource Name:plrblShowAudit.Text' because it loads after the max field length code, which needs to be loaded in order for the javascript to work when it executes.
It's not pretty, but it worked
<script type="text/javascript" language="javascript">
var d = document.getElementById("dnn_ctr380_ModuleSettings_Settings_txtFileSize");
d.setAttribute("maxLength", 4);
</script>