Hiraghm, regarding your "Pi Model T" question, check this link:
https://trmm.net/TRS80_Model_100/
So yeah, in theory it's possible, given enough time, effort, and money.
Plus more than a bit of custom coding...heh.
Also - google "trs-80 model 100 raspberry pi" for other links and ideas
- there's at least one link I saw (but didn't visit) that talks about
certain sized "wide" HDMI LCDs that will fit the case (so instead of
using the old LCD, you could have color, and "emulate" the look of the
original LCD - to an extent).
Good luck!
Andrew L. Ayers
Glendale, Arizona
phoenixgarage.org
github.com/andrew-ayers
