Personally, I think people get way too caught up in the LT vs. RT stereotypes. First of all, not all LT's are twinkle toes guys. Sparano coached Flozell Adams to multiple Pro Bowls, and Flozell uses a huge wing span, technique and strength to keep runners off the edge. Walter Jones really isn't nearly as athletic as he used to be, again he uses mostly wingspan and strength to protect the edge and push pass rushers wide. Frankly, there have been a couple of offensive tackles drafted in the past couple of years based solely on their supposed "footspeed" and they suck (DeBrickshaw, Robert Gallery). Offensive lineman is still a position of winning at the point of attack, no matter what kind of "feet" you have.
Second, you need good pass blockers on both sides in today's NFL. The idea that you just need a great pass protecting LT and you can stick any ole' behmouth at RT is an antiquated viewpoint, IMHO. First of all, most teams these days try to put good pass rushers on both sides. Strahan/Osi. Freeney/Mathis. Merriman/Phillips. Teams with just one pass rusher rarely just leave him strictly on the weakside ... most of them flip them from side to side looking for the best matchup. You better have guys on both sides that can pass protect against an elite pass rusher.