imagine a card that said "you may put a land card from your hand onto the battlefield untapped." would that work the way I want it to with elfhame palace?

No. The Palace is entering the battlefield, so its replacement effect would apply.

unfortunate. how about "Lands you control enter the battlefield untapped."? never mind I just reinvented amulet of vigor

I was going to suggest "put a land card onto the battlefield and untap it", but then you could combine it with anything that triggers of of lands entering the battlefield (like any landfall ability) to tap a land that normally enters untapped twice, couldn't you?

nah, triggers don't go on the stack until the current effect finishes resolving. that'd work.

Right. Well, then I suggest that wording for your hypothetical card. You're welcome.

I realize this is a pretty old thread, but here's my approach to making this work: