I really hope this works out not only for the Acela, but gets expanded to the system as a whole.
A couple days ago I had to make a number of ticket bookings for train travel through Germany and was pleasantly surprised that I could now select not only which seat I wanted to sit in, but even which coach.
Which is nice, because I was actually able to select "seat 17" in the first coach on one of the InterCity Express trains (my screen name and favorite seat on any train).
Actually I have a pretty good idea what it takes to do this sort of stuff since I have been peripherally involved in similar projects, most closely with the system used by United Airlines (SHARES). Also have followed the work of the folks who did the system used by Indian Railways, which by the way has assigned accommodation for all reserved accommodation, which if anything is way more complex and massive compared to anything that Amtrak could conceivably dream of, in terms of number of stations served, number of trains operated, number of seats/berths per train and number of passengers carried in reserved accommodation. It really is not as spectacularly difficult as is made out by folks here, and is not really rocket science either.
I agree with jis that if a country like Germany or India with much more complex routes and diverse rolling stock can figure it out, then it shouldn't be all that hard for Amtrak to do.
Perhaps a good way to go about funding this would be to do as the Deutsche Bahn (German railways) does, where you have to pay 4.50EUR (about $5.75) to reserve a seat?