I'm getting to the limit of the advice that cam be offered across a forum, esp. since Crash Bandicoot is less than 74 mins. But three more points to try and help:

1/
For the large DVD rips, I woul d now have pointed you to the post I made on Friday concerning rips > 650MB. You should try that anyway with your earlier problem.

2/
In relation to the Crash Bandicoot problem, I have found the odd occasion where Paradox UP doesn't work (before I got the OrigaChip), then the ASA Patcher did the job in those cases. You should check two things here:

a) There should be a file on the game you are trying to boot called: PBPX_952.02
(The original game will have this file called SCES_nnn.01 or something)

b) The SYSTEM or SYSTEM.CNF file should point to PBPX_952.02 when inspected with NOTEPAD.EXE

3/
You may, of course have more than 1 problem. The earlier issues being > 650MB and the Crash Bandicoot being a bad download. Does anything you copy from an original with CloneCD work? I think we ruled out a problem with the SCPH 10000 because you could replicate the problem with the 15000.

Keep us posted.