Not sure if this has been done before, but here I think this an interesting and contemporary "what-if?" When Texas Governor Rick Perry jumped into the Republican Presidential contest in August of 2011 he was perceived as a front-runner and strong challenger to Mitt Romney. But as we all know, his campaign quickly imploded due to a number of gaffes and embarrassing debate performances. This challenge is to have Governor Perry win the Republican Nomination for President, with or without the gaffes, in the most realistic way possible.
Well, it would first help if he hadn't engineered, with the help of the Texas Republican Party, an environment where he didn't face anything like the scrutiny he did during the Presidential election. It would also help if George W. Bush hadn't ruined Texas' reputation for Presidents just prior.
Putting those together, perhaps you might have something like this:
Somehow (waves hands) Kay Bailey Hutchinson doesn't run for the Texas Special Senate election in 1993. Perhaps she decides she would like to continue advancing within state politics (she did make a go at the governor's in 2010...). Therefore, she decides to run for the governor's race in 1994; Bush decides he'd rather be a senator than a governor, and ends up easily defeating Bob Krueger. And so he disappears from our tale, destined to become a respected senior figure in the Republican Party...
Hutchinson faces a harder fight, but does defeat Ann Richards that year. She goes on to win reelection in 1998, as well. On the same ticket for the Lieutenant Governor's position is Rick Perry, who ends up winning that position. Unlike Bush, Hutchinson does not decide to make a move for President in 2000, and instead quits the governor's office in 2002 (incidentally, this sets a record for length of time spent in the Governor's Mansion by a single person serving consecutive terms), passing the torch along to Perry, who wins the Governor's Mansion for himself. In 2000, Gore wins the Presidential election by a slight margin (there is Republican grumbling about how he "stole" it--he wins both the popular and electoral votes, but only by a slight margin).
Two years later, in 2004, Rick Perry decides to go for the presidential nomination; with the mediocre economy and no "war" bump (the al-Qaeda plot was rolled up early on and most people still have never heard of al-Qaeda or Afghanistan; Saddam still rules Iraq), together with 12 years of Democratic occupancy, the White House looks up for grabs. Despite having in some ways the thinnest resume of all the Republican contenders, Perry still manages to grab the nomination, largely on the strength of the Texas economy, and largely coasts to victory against Gore. Badda-boom, Perry's in the White House. Of course, he's a
different Perry.
I should probably note that I envision Hutchinson making a move for the Senate in 2002, which unlike her foray for the governorship back in 2010 would probably go well for her. No Tea Party or any of that, and I imagine she has a solid record as governor to go on.