Just a few days before this new piece of equipment was introduced, I had already tried that w/ mine (the Gold's Gym one from Wal-Mart that's on the website for $144 and in the stores for $134) and determined that it worked great (I weigh 125 and am 5'2" tall). I will obviously be very cautious to make sure the barbell w/ weight plates STAYS stable as I am using it, but it seems very stable to me at this point. I had tried it two ways, as a hanging cross-legged pullup bar (like we see Cathe doing in that photo on the blog) and as a lying one from the bench. Both seemed to work great.
When we bought the squat stand 2 weeks ago, my husband took the center support bar to a metal fabricating shop, and for free they cut the bar's length down so that when it was bolted together, the squat stand is now narrow enough to fit my 5' barbell. Now the weight plates are on the OUTSIDE of the supports, and it will serve all of my needs for STS - squat stand, pull up tower and separate inclined bench. PLUS it takes up about 12 - 15" LESS width than it did before he cut the center bar down - which means it's way less overwhelmingly large in my workout room.