You know, I *know* that I've heard that the SC Corridor extension to Memphis was a done deal, but I can find no source for it--it shows up as under consideration (usually a dotted line) but nothing else.
That's really the next big thing, in my estimation, vis-a-vis passenger rail transportation in this country. The past year has really been a watershed for a lot of little things that bode well for the future. Namely, just about everyone has finally agreed that the way to reach parity with other first-world nations is to do so incrementally. The latest Trains Magazine contains a column that recognizes this fact, and the very same issue highlights Amtrak's incremental fleet plan.
The designation of the corridors was a good first step, but the SC Corridor was designated a decade ago, with the intervening years spent staring at a map and little else. TxDOT's creation of a Rail Division, as well as the aforementioned funding of the Heartland Flyer, shows that even our state is starting to get it. Will we be on the lists with the Californias, Floridas, and so on? Nah, not for a while. But the FRA slap in the face actually did light a fire under Texans, and I think it'll yield results down the line.
At any rate, my point is that now that the tide is shifting, focusing on the connections between the corridors should begin to happen.