I've just installed it on the Ematic XL Pro II Android Tablet I'm reviewing right now. The install process was slightly complicated but it worked. You should seriously consider trying it.
You can find the install file over at XDA Forums. Copy the APK to your Android tablet over a USB cable. Then unplug your tablet, turn it on, and find the APK in a file manager.
Note that there is some risk involved. The first thing I had to do to install the new version of Google Play was delete the older Android Market app that I installed over the weekend. They're not compatible, and my tablet declined to install the new app on top of the old. Considering that I didn't know that I would succeed, that was fairly risky. You might not want to take the same risk.
But if you got Android Market using one of the sets of instructions I posted then trying to install gPlay is probably going to work. And if it doesn't you should be able to reinstall the older Android Market.
Worse comes to worst, you can always do a factory reset and try again.
Update: And it looks like I will have to do that reset. Google Play has stopped working on my Ematics tablet.