Ordinarily invalid districts have to be fixed before the subsequent general election, which means this November. That was the case in Texas in 1996 when the SCOTUS struck down a couple districts that June. They ended up holding new primaries to coincide with the general election for 13 redrawn districts, followed by a December run off. That's because GWB didn't convene a special session of the legislature to fix it and so the courts imposed a new map.
Might that possibly solve the GOP's 'Replacing DeLay on the ballot' dilemma?