I responded to your prior thread and you also mentioned Tulane so I will include their information in this post. As the title of your posts suggest I will not beat around the Bush the odds of getting a biglaw job from any of these schools is minimal. SMU will give you more of a chance than STCL, but maybe a 5% increase and it is 14,000 more a year sticker price and as I mentioned you can likely obtain a large scholarship from STCL if you ask. If they don't give that to you then SMU might be worth 14k more. However, if STCL offers you free tuition the rest of the way that is a savings of 52,000 combined with the additional cost of SMU at 40,000 a year. So you would get out 132,000 less in debt. These are serious numbers considering your odds of big law out of SMU will not be much better than STCL. You also have to consider moving from Houston to Dallas this may or may not be a big deal to you, but the reality of changing cities can have a significant impact on how you perform in law school.
The simply reality is the life of a lawyer is not how T.V. makes it out to be. Firms do not wine and dine students for the 48th best school because they were on law review. Many recent grads from schools of the caliber you are mentioning start out making 50-60k and after a few years of experience often make in the six figures, but it takes time. REALITY OF BIG LAW
Many people strive for this few get it and those that do often do not enjoy it. I have several friends from Harvard who worked at Cravath for a few years and said it was awful. They went to work as in-house counsel at various tech companies and took a paycut, but love what they are doing. Simply put biglaw is not for everyone it could easily be for you, but before spending $100,000 and changing schools you way want to research more if you have not done so already. BYU INTERCOLLEGIATE JOB BANK
This is a great site where you can essentially see the job postings that every law school is offering. Here is the link username jobfind password fall2012. South Texas, SMU, and Tulane are on there so it might worth looking at the jobs they are posting before spending 100,000+ more dollar accruing interest and changing from an environment you are doing well in. LAW SCHOOL TRANSPARENCY NUMBERS
Law school transparency is a really good site that shows actual reported salaries of students coming out of each school. You will notice most schools have huge gaps of unreported scores which I assume means unemployed, but I cannot say for sure. There is also a chart that shows student debt/salary ratio which might of help. I have attached the links for SMU, Tulane, and South Texas below. SMU does account for most of their students which is great, but it does not appear that one graduate made over $130,000. http://www.lstscorereports.com/?r=txhttp://www.lstscorereports.com/?school=smu&show=sals
(SMU REPORT) Pretty good accountability, but not one graduate made more than $130,000. http://www.lstscorereports.com/?school=tulane&show=sals&class=2010
that is 2010 info nobody reported 2011 so that is a red flag) (TULANE) http://www.lstscorereports.com/?school=southtexas&show=sals
(SOUTH TEXAS) CONCLUSION
If you really know what biglaw entails and there is nothing else you want other than that then SMU will give you a better chance than STCL. However, it will be a 5-10% chance increase and you will be paying a lot more money for that 5-10% and you may not like the switch from Dallas to Houston and being away from the people you met during 1L.
If the money and potential of not liking the new school are worth a 5-10% chance increase to work in biglaw then go for it. However, be prepared to spend a lot of extra money and end up working alongside people from STCL in the future. It is your call.