I tested OpenMSX 16.0 with Pinephone Keyboard

Easy install:
sudo apt-get install openmsx

It has ready made icon for Maemo! But without right configuration you have to start it from X Terminal, example command:
openmsx -cart lily.rom
(lily.rom, was name name of cartridge rom image file)

I only made fast simple rom cartridge test. All seems to work very well. I used default machine setup (that lacks Basic-rom!), because it wasn't easy setup specific MSX computer, because separate OpenMSX Catapult configuration GUI has too much graphics problems. I tested Catapult version 16.0, but it is not latest, so if somebody want make it more Leste compatible version here is latest sources: https://github.com/openMSX/catapult

If somebody know how to setup specific machine configuration to default with this version of OpenMSX, it would be nice get info, because it seems to be different than older versions of OpenMSX.

I tested PowerMac emulation with qemu-system-ppc

Easy install:
sudo apt-get install qemu-system-ppc

Hard to configure, try find some ready made script+disk image.

I tested with Pinephone Keyboard with mouse, but might run even with N900 almost usable speed, if don't try emulate more than this Powermac 6200 75Mhz with 32MB RAM: http://apple-history.com/6200
and not more than with MacOS 8.1

I only did fast test that it works with Pinephone Keyboard and it would be fun hear Droid4 and N900 tests with different Mac OSs, especially System 7 (might better emulate with SheepShaver) or Mac OSX (would be very slow).

EDIT: It is normal that short time in start it gives some errors about display and keys and is slow to start.
EDIT2: QEMU has two mac machines "mac99" minimum OS is MacOS9.0 so if you try older OS you should choose "g3beige" and oldest OS should be MacOS8.0. So System 7 have to emulate with SheepShaver.

This Symbian OS/N-Gage emulator would be nice:
https://github.com/EKA2L1/EKA2L1
Can somebody try to compile it to Leste?

Has anybody tried run some PC emulation? I know that Wine is not emulator, but has anybody tried run Windows programs with Wine with this https://box86.org/ ?

I tested Dosbox 0.74-3 with Pinephone keyboard.

Easy install:
sudo apt-get install dosbox

Fullscreen doesn't work, it is missaligned too badly. Maybe somebody, skill full enough, should make real Maemo Leste version.
BUT scaled window works!, have to edit config file using command:
nano ./.dosbox/dosbox-0.74-3.conf

change lines to:
windowsresolution=1440x668
output=opengl

ScummVM: OK, it's no emulator, but I guess it fits here...? Installation, adding games and starting them is no problem! I just had to use the command-line, because mouse (touch to mouse) isn't working. The cursor seems to act in a digital way - always at the edges of the screen. I tried editing the /home/user/.config/scummvm/scummvm.ini, but to no avail. Any suggestions how to make touch to mouse work?

If i remember correctly, that's a well known bug. You should run ScummVM in window mode, not fullscreen. This way the mouse should work.

Yup! Thanks (yet again)!
Shame though with the title bar at the top...

Have anybody noticed that Pinephone screen resolution 1440x720 would be good for emulate old PC with Hercules graphics card (720x348). Easy get pixel perfect emulation with doubling and just leave some room for menubar (24 pixels). Actually also N900 800x480 with some black borders is not so far away. It would be nice if some body can make custom Maemo build of Dosbox with more direct screen usage.