[scandox]

Not a huge amount of hosting companies support Bring Your Own IP do they?

[tomatocracy]

More do than you'd think.

But for IPv4, true BYOIP isn't really possible for less than a /24 block, which is overkill for just selfhosting personal email.

It also usually involves needing to set up a company to own/lease the block if you haven't already got one.

[xolox]

By definition most of them won't because it's a complicated mess.