Hmmm can I use Atari Lynx LCD panel?
Can I use those $150 Ti graphing calculator with color screen?
not listed on the first page. j/k
Many portable DVD players can be used as many of them has A/V input. Depending on the design, you may need to leave the DVD board intact (OK to remove DVD motor and laser) and either hard wire the A/V in/out to be input only or switch to external input only (both should disable onboard DVD functions).
5"-7" portable DVD that won't play DVD but has working LCD can often be found for under $10 plus shipping. Keep in mind older game systems don't look good when stretched on wide screen so check for 4:3 panel for older game systems.
Most 4:3 LCD panels for portable DVD player are using CCFL and would require LED mod to get better battery life. Widescreen LCD is a hit or miss but older, broken players are likely using CCFL as well.