For those lurkers who might find their appetite whetted by this thread, this is what I've found for available products:
Classic Traveller Materials
As plugged several times upthread, Marc Miller's Far Future Enterprises (FFE) produces CD-ROMs that collect older, out-of-print materials as PDFs. In addition to the Classic Traveller CD, there's also one that collects early issues of the Journal of the Traveller's Aid Society, and it looks like one is forthcoming that collects CT material produced by third parties such as FASA and GameLords. There are also CD-ROMs available for MegaTraveller and other GDW games.
FFE also produced a series of hard-copy reprints of CT materials. These are available through many vendors, but here's e23's selection:
http://www.warehouse23.com/search.cgi?comp=Far+Future+Enterprises
T20 Materials
It appears the core d20 Traveller book is out of print, though copies are available through several online vendors such as
Amazon. Note that there were evidently two printings -- I assume the second one included errata. The most common price is $55. but keep in mind this is a 464 page monster. The cheapest price I found was at Books-A-Million ($31), but I'm not sure if this is the first or second printing, and it's not clear if BAM will be able to fulfill the order.
The T20 book is also available as three separate PDFs, which are based on the second printing of the core book. Here's RPGNow's page for QLI/RPGRealms, the publisher of T20:
http://enworld.rpgnow.com/default.php?manufacturers_id=325