The sex dummy is pretty hot, they'd be so much less trouble than a wife or girlfriend, the conversation would be better, Atm's would be as standard and your butterfly work would get awesomely sticky. Anyway back to a serious response, I can only get to training once a week so most of my training is done with my grappling dummy. I think you can learn a fair bit with the grappling dummy, obviously not ideal, but better than nothing.
Grappling dummies are quite easy to make, I made mine for around £40, it is poseable and is great for practicing the squeeze in all positions. my girlfriend just came down and read this and now has the sulks. That doll is looking more beautiful by the minute.