I day dream about having one and using it when working. Years ago when I first started I use an older wooden 1-1/4" rabbet plane and my standard jack plane. After knocking knuckles a few times I easily switched to a slick for finishing tenons. This version you speak of has a adjustable handle, right? Yeah, here it is.....http://tfguild.stores.yahoo.net/li1014rapl.html
If the extra cash was available I would give it a go. I sometimes end up scooping the tenon with the slick, a little too much light under the straight edge, better than too fat I tell my self.