I've never seen one. I just don't think there is enough demand for any company to make after market parts for them. Most people are going with the Ruger 10/22 to tac-out. You may want to look at stepping up to the Ruger if you want a tactical look .22LR.
I also have the 702 and I haven't been able to find much for it, not even the 25 round magazines. I went ahead and got a 10/22 and the 702 hasn't been shot in a very long time. If you're wanting a .22 you can customize easily, I would recommend you get the 10/22 and leave the 702 as is.