Why can't you just cut the countertop to size and skip all the sliceing and reglueing? There's no reason what you propose won't work but you could as easily rip some 1x6 to build one from scratch and save yourself $200.

Because she’s looking for an end grain top, not an edge grain offered by LL. Reading some of the reviews, some of them may be partially laminate and plywood which would rion your idea and $250 table if you cut into it. Last but not least, butcher block surfaces will require maintenance, otherwise it will crack. And if not oiled evenly, will start to warp.

For that large of a table, I would suggest doing the edge grain as it will likely hold up better. The main reason to do end grain would be if you’re actually going to use it as a cutting board, the ends will hold up to knife abuse better. And of course for looks as well, but edge grain can look great too.

One concern is that an edge grain countertop will expand in depth and height, but not in length. An end grain countertop will expand in depth and length, but not height. So if there is a wall at both ends of the countertop, you will have gaps or worse. Another is that liquids will seep into end grain more than face grain.

Have you looked for a local millwork or cabinet shop that could make one for you? That would avoid shipping and you could get it made exactly the size you want. Maybe cheaper than buying online.