there is no real point anyway most tiptronic gearboxes will still over ride the driver and the shifts are still the same speed anyway, if you could be bothered doing this why not just spend money on upgrading the box and getting manual shift kits put in anyway, better just to a manual conversion. It would be a lot of arsing about and generally most good auto boxes will be faster or the same speed whether in tiptronic or just in sports mode or drive for that matter with a good adaptive box.
I have seen a range rover 4.4L V8 when at motor mag for work experience, sports mode it would rev to 500rpm off the redline and then in tiptornic mode it would let you hit the redline and then change if you hadn't anyway. Most cars there really isn't much point hitting the redline because by that stage the engine would be developing more power in the next gear anyway.
On a side note the falcon gear boxes in tiptronic will just sit at the redline, only useful if you wanna do a burn out and lock it in gear.