Mod-less TBB are available for this gun. They have standard and custom lengths available.
You can contact Travis Humble at
contact@cradleairsoftsoft.com. Here is a note from him, Barrels are still available and can be custom made to any length you specify. Cost is $45 + shipping. US Domestic is $5.75 and International is $14.00.
You can also contact cansoft.biz AKA on ASC KGBB he has mod-less EdGI TBB available. PM him, he seems pretty knowledgeable on it.