Hi,
I work in composites building America's Cup yachts.
We use many different types of epoxy resin. You would be surprised at the array of strengths available from different types of glue. One rule of thumb is that the faster the air drying cure rate, the weaker the final strength of your bonding. I just got myself a C40 after much deliberation as to which process of construction was best, i.e. Female moulded in 1 piece or tubes bonded into lugs. I went to the Colnago in the end, as that's the frame I reallly wanted.
I checked out a Trek 5900 before I made my decision. I'd heard that this was a moulded frame, but looking closely you can see that this frame uses tubes bonded in a male/female type joint.
Ultimately I think it is tooling costs that govern how the frame gets built for composite frames. The tooling must suit many sizes of frame (lugs) or limit the mould to 1 size of frame.
See you later !