I have tried the njoy 2.0. I'm pretty sure it's only 1 pound, last I checked.
Try this one- it seems to have a relatively narrow neck, and the 50 mm (2 in.) diameter weighs 2.47 pounds.
You can even get a detachable handle for it, which would add quite a bit more weight
Then there is a 2 in. max diameter version of the jewel plug, which weighs 2 pounds:
If you want to try a heavy plug with a wider neck, there is this one:
For a custom plug with a narrow neck as well as a narrow base, check this one out (pictured with a chastity cage, not included):
That one can be ordered from http://www.steelwerksextreme.com/butt-plugs
Now for e-stim- This seems to be the best option I have found:
You can use a remote control for it:
* I am not affiliated with any of the above manufacturers or retailers.