Radians offers a custom molded ear plug that you can make at home for about $15. If anyone is in need of hearing protection I would highly recommend them. I shoot competitively and I can wear these plugs all day without any discomfort. I also use them on my motorcycle under my helmet - again work great.
I was also able to successfully mate these to my klipsch custom 3 iems. The fit is amazing and I can now use them under my helmet as well with no discomfort.
The process I used was to take about half of the material ( a two part putty ) knead it together as per the instructions and insert into the ear.
As soon as I have the material far enough in my ear that it won't go any further comfortably, I insert the iem as if I were going to wear it normally ( don't worry about damaging your drivers as the pressure inside the driver will keep the putty from getting too far in).
Wait about 10 minutes for the putty to set up a little and then remove the plug and let cure ( either until you cannot make a dimple with your finger nail or over night)
After curing remove the iem, take a small drill bit (.1 - .125in ) and drill a hole connecting the tip of the plug with cavity left by the iem ( I did this by hand - no drill required )
Make sure you have a clean hole with no leftover shavings and re insert the iem into the plug - enjoy
Hope some other people will try this out - I am really impressed by what about 15 minutes of work can do for comfort and stability
I think you could make this work with something like an iBud too but I think it would work better with something that has a removable tip.
I'll post pics when I get a chance
These kits are available at Wal-Mart online, Scheel's or your local gun store