I'm pretty sure Bethesda wouldn't mind that at all, actually, and they are suing for damages as well as a solution to the problem, which means they are looking for money and assets. Interplay has little money, if any.

If they lose the rights to the original Fallouts, the problem isn't solved (it actually might get worse), and if Interplay goes bankrupt, they won't get nearly as much as they'd like.

Well, with the details presented to us, I don't see any way Bethesda could lose the case, really. There is no risk for them, only reward, unless there is something we don't know about in Interplay's favor.
And as has been said, if Interplay needs to turn over more money than they have, they will either sell IP for it, or offer IP to Bethesda, either of which Bethesda would like I assume.
2K games is doing the same thing to 3D Realms right now.

Ya, Interplay has screwed up big time by calling this the Fallout Trilogy. I picked up this game collection a couple of years ago. It was published under the GSP White Label series and was called Fallout Collection. With All three titles on the cover (Fallout Tactics and not Fallout 3). If Interplay loses this lawsuit, then I'm sure Bethesda will ask for IP's for compensation, because Interplay just doesn't have the money.
If Bethesda does get games, they might still be sold on GOG. But I would buy up games I didn't have, just in case.

Not to sound like a jerk, but I explained the legal implications above, so most of the hypothetical/assumption posts made after it are moot.
The only games that you, as a legal owner of said title via this service, or any comparable one, will lose the right to download in future are those that have licenses WITHIN them between the PUBLISHER and a THIRD PARTY, such as the NHLPA, Van Sneakers, General Motors, etc.
And even then, games with said licenses in them that are REMOVED from the catalogue will not nessasarily be denied downloads for existing owners.
SO in summary, NO Fallout or Interplay titles you currently own will be affected by this lawsuit, NO MATTER WHAT the final verdict is.

Strictly out of court, it's possible, I suppose. Of course, this is assuming that Bethesda are interested in Interplay IP other than Fallout. They seem inclined to take only that which they'd put to use.

Well, I'm specifically concerned about several Interplay titles that I haven't bought yet. :|

If Interplay declare bankruptcy as a result of this, they won't have a choice but to sell off all of their IP. It will go to the highest bidder and there won't be any guarantees regarding what will be done with that IP or whether deals with services like GOG will be honoured.
In short, it's a possibility. Interplay have been failing for a decade now. It has only been the sale of Fallout that has kept their heads above water. Now it's that very same IP and their misuse of it that is pushing them back under.
If they've made enough through the sale of their old IP to survive this, then it might not end so badly. But then not all such sales were as legitimate as we were lead to believe. No doubt some of those profits will be seized too.

A good example of this exact thing is FEAR. That game was owned, both the name and the distribution of the game, by Sierra. When they folded, bought by Activision, the name went to Warner Bros. and Monolith, the distribution went... who knows where.
The game was pulled from Direct2Drive shortly after. If you bought it beforehand though, you can still download it. So I would advise everyone who wants them to buy the Fallout games when they can.
Bethesda have been buying up a lot of IP and such lately... forgive me, I forget the examples, but there have been several stories post-id recently that show Zenimax wants to become another EA/Activision.

Aliens was so called because a cheesy Italian film decided to use the name Alien 2, as if to suggest it was a sequel to Ridley Scott's film. It's a shame that the brass balls of doing so was all the film had going for it.

I'm going to make a small, $20,000 movie and call it Titanic 2.

Yet more hyperbole bullshit I've heard a lot of recently.
I've seen nothing from the company that would suggest it was going to begin producing cash cow titles, like The Sims or the Rock Star/Hero games. I haven't seen any signs of them slapping ludicrous price tags on their titles, even when they have taken many years to make. Or adopting grossly different pricing strategies in different countries. I haven't seen any signs of them adopting malicious DRM policies or otherwise treating their customers like shit.
I also haven't seen them buy up IP without putting it to use. About the closest they've come to EA and Activision is producing some DLC of highly questionable value. Add to that the fact that id sold out to them because of the creative freedom they respect and the lenient deadlines and I really don't see why people bother with this paper-thin bullshit rhetoric.
Zenimax are far from perfect, hell they've got a crook running the company. But given the rest of the games industry, they're practically saints.
People may find it shocking that they want to expand. They may be butthurt over Fallout 3 not being a carbon copy of its decade old predecessors. But until I actually start seeing some signs that the company is changing for the worse, that's one bandwagon I've got no interest in jumping on.

[url=]http://www.imdb.com/title/tt0472570/[/url]
Too late! LOL

I don't gave any problem with Zenimax, for the record, I have just seen a lot of industry news about them expanding and buying up titles.

Which is a good thing, really. But when most people compare them to EA or Activision, you better believe they aren't looking to compliment Zenimax.