No Spam wrote:

My friend mentioned an end-grain cutting board, but that seems like a
great deal of work. Extra work for the cutting, extra work for the
glue-up and alot of extra work for flattening. I don't have a wide
belt sander to flatten it.

It's about twice the work. You rip it and glue it like an edge-grain
board, then you plane it flat/smooth. At this point you have a
perfectly fine edge-grain board. Then you crosscut it, flip each piece,
and glue it all up again. If you make one edge strip about half the
thickness of the others, you can offset every other glue joint in one
direction to minimize the likelihood of splitting.

Best bet for flattening is a low angle jack plane...sanders leave grit
in the wood, which is bad for knife blades.

If I did end-grain - is hardrock maple still the right wood?

Sure. I made an endgrain cutting board out of cherry and hard maple,
about 2" thick.

One thing to note...endgrain has very little strength when thin, so
you'd want to support it somehow. It will also tend to temporarily warp
if one side absorbs moisture and the other doesn't.

Chris