If you google "grappling dummy" a couple good products show up.
The Submission Master, Bubba and the Bubba II.
I loved the idea of a dummy. Train any time, get a ton of repetitions in, and you have a partner that didn't care that about the hundreds of armbars, leg locks and chokes going on.
I wasn't sure that I liked the price though.
A little more investigating brought me to a couple DIY projects to make a homemade grappling dummy. I found some good examples: el jefe and another example that I used as a template to build one.
My kids thought building a dummy would be "awesome". My wife - not so much.
Below is part 1 of the dummy chronicles.
Heavy gauge wire. See the mop head there as well.
I got a ton of duct tape and had some wood dowel left over from my home made nunchucku project.