Blade Tech sounds like what you need. Since your barrel length precludes you from IDPA, the speed rig will work great for you. Approved for both USPSA and ICORE. Here's the link...
Pro-Series Speed Rig Holster
While the 6.5" barrel model 25 is not listed, Blade Tech will generally make you a holster of the proper specs. I don't believe that there is any extra charge, but it will require you to call and talk with them, or e-mail them about availability. Depending on options chosen it will run $80 - $90.
I don't shoot ICORE so I'm not sure if their rules allow an under/over belt system (they simply said the holster must be attached to your gun belt). If you intend to use such a system, then the Tech-Lock attachment would be recommended. If the holster will be going on the belt that holds up your pants and is threaded through your belt keepers, then the Stingray attachment method will give you more flexibility in placement.
Also for consideration if using an under/over belt system is the Double Alpha Racer Holster at $130. It will accommodate any N-Frame regardless of barrel length - so if you have multiple N-frames in various barrel lengths, the added cost may be worthwhile...
DAA Racer Holster - Light Weight USPSA / IPSC / IDPA Holster for All Levels
Good luck.
Adios,
Pizza Bob