I am running Splunk 6.2 and have modified a report with custom line colors etc. on a dashboard using simple xml. I would like to be able to share this single panel on my dashboard to an external webpage. I can not use the unsecure method mentioned elsewhere. I also can not use the embed feature from the report since it does not contain the customizations needed. Thanks in advance.
I don't think there is going to be an easy answer for this. Retaining customizations is always a bit of a challenge.
I will mention one other option. You could export the data from Splunk into something else that reproduces the report for you. I use the Google Import/Export app to send data to a Google Spreadsheet which is rendered into a report. I like this method because Splunk pushes the data out and therefore seems more secure (I'm not providing anyone or anything access to Splunk). I'm guessing this method is not ideal for you though because you would need to re-produce the customizations but I'm mentioning it just in case.
In the current version (v6.2.2) since embedded reports are not an option for you I think you will need to use the SDK. Specifically I'm thinking the javascript SDK will be best suited for this task http://dev.splunk.com/javascript