What is the difference between leaving residual sugar in the wine and adding a bit of sweetness back in later? You could also keep a bit of juice outand add after fermentation instead of adding sugar. Full bodied wines are higher in alcohol and if you stop fermentation early, you will be compounding the problem.
That said, you may stop the fermentation by shocking the wine and yeast. When it is almost as dry as you want it, throw it in a refrigerator and add your k-meta as a double dose. The combination is enough to stop most fermentations that have slowed way down since they are almost dry. You will likely have a bit too much sulfite, but you need it to help keep the yeast at bay.
Another way, which would help body, would be to add everkleer or brandy to boost the alcohol level and kill the yeast left. This is more along the lines of a port style wine.
Good luck. I hope you can get the results you are after.