Good short-term fix until quality repair option surfaces
About 3 months ago I got a small tear (1/2 inch) on the side of the driver's seat of my RX300. Looked into many options for repair kits (including this thread) and just haven't gotten any confidence on a long-term solution. I used several types of tape (electrical, movers, painters, etc.) since the cut appeared and it's now grown to over an inch. Wish I had begun using the option in the attached photos - 3M Health Care tape - from the very beginning. Works best since it's slightly flexible - for it's intended purpose cuts on the human body. It's not the softer fabric type health care tape. It's a little sturdier which I think helps. All the tape I had previously used were too rigid and therefore fell off after a couple days. The 3M Health Care tape has been applied once (directly covering the 1 inch cut, and one piece of tape on either side) and hasn't budged in nearly 2 weeks. I'm still interested in a long term solution but this might help you in the short-term too.