I have a relatively short hack that’s finished, with a few extra features yet to come (hard mode and supports). The first few chapters should probably take ~2 hours. It’s meant to be harder than vanilla GBA FE, but nothing like modern maddening modes (just don’t try the untested hard mode). Story wise, it follows a small band of mercenaries through the start of their career, as they get wound-up in a noble rebellion for the fate of the nation.
Anyway, cool thing you’re doing here, and I hope you consider my hack!