But if you had a great feeling 76, you could fool the audience, and maybe even yourself, without the extra (optimistic!) 25 lb +15 lb. for a case and 88.

To be honest, REALLY good piano action is all about mass... Mass in the keys themselves, not the support structure (although that is going to be additional, just to support the weight of the keys!). Lightweight keys feel no better than a plastic action. It has to be the full monty before any 88 makes sense, IMO. And there are NO full wood key 88's at 25 lbs.

Plus, think about it... Let's just assume it DOES exist. 25 lb. for the 88, and 25 lb. for the PSR. That's 50 lb. not counting cases (truth would be closer to 60 lb. before cases). A G70, which DOES have a great 76 action, heavy enough to play piano well, light enough (and rounded key enough!) to play organ well too, doesn't weigh that! Roland's RD700SX, considered one of the best 88 wooden actions is 50 lb. alone!

Add in a two tier stand (heavy duty enough to support an 88 AND a 61) and all of a sudden, 45 lb. doesn't seem so bad, now does it..?

If a compromise is possible (and anyone that plays a PSR keyboard knows ALL about compromise!), a good feeling 76 SAVES you 30-40 lb. over a good feeling 61 and an 88 for piano, and is still good enough for 95% of whatever piano stuff you WOULD play...

Just a thought...