I have been casually looking for a Smith& Wesson J-Frame Revolver AIWB holster to try and Blade-Tech told me that I should keep on eye on their new releases. Sure enough, Blade-Tech has a relatively new Appendix IWB Holster and they recently introduced a J-Frame version.
Their new straight drop (no negative cant) AIWB holster is made from Kydex. It features an injection molded plastic clip that is designed to function with a wide variety of belt types and widths. It is made from thinner material than what Blade-Tech typically uses so that it keeps a lower profile. it is even molded to allow the use of Crimson Trace Laser Grips.
Check out Blade-Tech.com.