You know, I can't help but wonder...if Amtrak can't get a bid for 40 Acela cars to work, why not seriously look at simply moving the Acela II order forward and reworking the existing Acelas as either a smaller second-tier express service or as a higher-end non-express service? As far as I can tell, the cars themselves should be reshufflable, so with 120 trailer cars (20 sets of 6), you could probably go to 15 sets of 8 (or 12 sets of 10) with a couple of cafes redone as "second class" cars. IIRC this was something of the longer-term plan, anyway, and it might free up some Amfleets. Moreover, if operated as a lower-speed service, it seems plausible that you'd be able to pop off the power cars and run the trains along non-BOS/WAS lines. At least from what I can tell, capacity is the big issue at the moment.
On Superliner IIIs, I agree that 25 is too small, but I'm not sure where the lower threshold of "workable" is. Would 50 cars of a single type be large enough to be economical? I might well see a market for the use of 50 Superliner sleepers (though it would be a stretch at the moment, as long as the current trend holds at least modestly well...well, a 15% increase in sleeper demand over 6-7 years isn't too hard to envision). Coaches are a bit harder to see at this exact moment (the order of 130-ish cars for the states should do some real damage to this shortage for the moment, and it seems plausible that this order could nudge slightly higher), and food service cars just aren't going to be "on" in large numbers unless a lot of other stuff is also coming down the pike (not to mention that a few of those are likely getting freed up by the state order as well).
On Superliner IIIs, I agree that 25 is too small, but I'm not sure where the lower threshold of "workable" is. Would 50 cars of a single type be large enough to be economical? I might well see a market for the use of 50 Superliner sleepers (though it would be a stretch at the moment, as long as the current trend holds at least modestly well...well, a 15% increase in sleeper demand over 6-7 years isn't too hard to envision). Coaches are a bit harder to see at this exact moment (the order of 130-ish cars for the states should do some real damage to this shortage for the moment, and it seems plausible that this order could nudge slightly higher), and food service cars just aren't going to be "on" in large numbers unless a lot of other stuff is also coming down the pike (not to mention that a few of those are likely getting freed up by the state order as well).