Al,
another point of syntax. what you might refer to as 'notionally republican' is usually referred to in our media as 'ideologically conservative' Not that I like that notation any better, but it is in the vernacular. Thus, the US congress has long had an ideological majority one way or another, even during times of absolute partisan contol changeover, so your point is well taken.
what you may overlook, however, is a subtler point of rules, regulations, assignments, etc. The Texas 5 et al may have been part of an ideological majority, either way, but for majority/minority leaders/whips, rules, etc. all Dems (excepting Traficant) and all Reps (excepting sometimes Jeffords) voted with their respective parties. So a change from a "conservative democrat" to a republican is a real change. believe it.
Actually it's more for the purposes of comparing elections than power in the House etc.
This is what I mean by a notional result:
If the 2002 elections had been fought on the 2004 Congressional districts [this applies to TX only] the GOP would have won the most votes in each of the six districts DeLay screwed the incumbent Dem in.
So that's six gains for the GOP via the re-districting, however as Edwards pulled a houdini in Waco, the Dems gained a seat back.
Obviously in terms of raw power crunching in the House this is different. But it makes it easier to compare electoral results.
We do that over here every Boundary Change. Makes things easier for people obsessed with elections :-)
Check this out:
http://www.election.demon.co.uk/bcsum.html
Poll
