How is it that everybody always posts the Half-Minotaur template without also noting that there's a Half-Ogre template
on the very next page that does mostly the same thing? Or at least, for the purposes of this thread, the exact same thing: size growth.
D&D Wiki has the
Giantism(sic) Trait. You are basically a +1 Size Category version of yourself, with no ability modifications(beyond losing 2 Dex).
Thrall of Kotschchie is definitely good.
The problem with Deformity: Tall is that the moment you actually change size categories, you lose the benefit of the Feat... Kind of stupid. House-rule the pre-requisite as "Size: Medium or larger."
Inhuman Reach+Deepspawn+Extended Reach is a little steep Featwise, but if you're a Medium creature to start with, you're rocking 15 feet of Reach. 30 with a Spiked Chain. That's a diamond("circle") 7 tiles wide on a side. Be a Half-Illithid to start, finish Illithid Bodytamer(aka Illithid Lasher), grab Tentacle Extension items, and suddenly, you can suck brains from further than the Olympic Long Jump record.