Way, Weigh, Whey

As in, "There's more than one way to weigh whey."

Leader & Liter

Ah, the lazy American T. Responsible for so many homophones. Bid and Bit would never be pronounced the same here, but Bidder and Bitter often are. Wade and Wait – two distinct pronunciations. Waded and Waited – let's just say them the same, why not?
Here's an interesting little description of the tongue tap that we (and apparently Australians) are so fond of. UK English speakers apparently wouldn't hear these words as homophones at all. Which is just as well; when we say "take me to your leader," they'll know exactly what we mean.

Quarts & Quartz

-s – plural form of "quart," a measurement of volume.
-z – a crystalline mineral.
There is so much quartz in the earth's crust, you would measure it in tons rather than quarts.

Flour & Flower

Maybe we can call bakeries "flourist shops"?