You got it Lol.
a.) the bar will ruin the baseboards
b.) the bar will raise up if not held down somehow
c.) the bar must be able to pivot
d.) my t-bar unit uses a chest pad to isolate my lower back from the exersize. Many commercial units are just stupid frames with a pivot bearing and the bar with handles. For only $200-350.00!!!
If your lower back is okay for the lifts, then here is a suggestion: My unit has a 4x4 block with a 2-1/8" hole drilled 1/3 of the way through; that's what the end of the bar sits in, then the box at the end is just 1x material wrapped around the block, with a flat on top for the 25 lb. plate counterweights. That part would be all you'd need, with some carpet on the backside to sit against a wall with a plate on it to hold it down for you. You can either just grab the bar with your hands, or use a seated row handle as you said, or there is a way to do it with bicycle handlebars, but I'd be afraid of bending those. I personally want something that will not slide around when I'm pulling. I've seen it done with the ropes, but you need a great grip (aka Steve) for that. If you want to use an olympic bar, just drill the 'pocket' with a 2-1/2" to 2-3/4" hole saw, paddle bit, or Forstner bit. Go 1-1/2" deep.
With my bad #4 lumbar, I have to isolate with the chest pad, but I can go ****-heavy this way. For some reason I have awesome pulling strength...I remember using five plates back when I went to the gym.