You know, I'm also a sucker for a major height or age difference between the uke and seme. So I'll just give you a list of my favorite read. I'm sorry if it's not to your liking, because some of the characters in the list below doesn't really have that BIG of difference in height, but the uke is of course smaller than the seme. But don't just look at the cover/front page.
Give it a try though, you might like it. Have a nice read. ^ ^
Sign
Here U are
Hidoku shinaide
Mayoke no darling
Totsugimasen Kara!
Kamisama no Iutoori
Eyes speak more love than the mouth
He, Him & Us
Mauri to Ryuu
Ookami wo Karu Housoku
Nise x koi boyfriend
Mother's spirit
Hello guys, can u recommend me some yaoi manga where the couple have a big difference in height or size. For ex, the seme is so big and tall while the uke is small and petite. Thank youuuu(≧∀≦)