What I'd love to see (but likely lack the skill to, even with Claude Opus) is PowerPC. Haiku would look great on an iMac G4.
Also, don't dismiss what you're capable of with Opus / AI! I keep discovering I'm not being ambitious enough with my AI work. Not that I'm an expert or anything, but the models keep being more capable than I imagine, with enough coaxing. I keep needing to set my sights higher.
My LLM experiments have become more ambitious as the tech has improved. Porting a decompiled SNES game to the Dreamcast is the latest (80% complete) victory.