House customization is not in the game just yet, so you can't customize a house to have herb plots. You can buy one though through the real estate link on the home page.
You can't have a 50k with herbs yet. They're going to be putting in a housing customization system eventually where you build your house from scratch exactly the way you want it. But you'll have to wait until then to have a chance to have herbs in a large house. Until then, you'll have to buy a herb house or work out a deal with a friend to use theirs or use the community herb garden.
Street projects only show up when the devs start some for a new region. We can't start them ourselves. You might want to join the New Streets group to keep up with when they are available.
I think they generally keep an eye out for projects and can let you know when a new region opens and has projects available. Probably the best way to keep up with such things it to join their chat when you're in game after you've joined the group.
There is as yet to guarantee that house customization might include cross-ecosystem growing capabilities. Many people have wished for this, and the wish has slowly morphed from "I would like" to "they might" and right into "they're gonna." *I* have not seen any indication from TinySpec that you will be able to grow herbs outside the bogs, or will be able to grow produce in the bogs, and I would encourage people to slow down and not get their hopes up in this particular case.
@WalruZ, There was a bug in the game one night where everyone could cross-plant the other crops in their gardens - one of the devs came on the forum and said it was a mistake, s/he was trying something out for himself, and had set the parameters wider than s/he meant. So it's definitely something they've been working on, which puts it at least on a "they might" level.
@oscarette, that bug was just before pumpkins were introduced for first time, which grow in both crop and herb plots. So I wouldn't use that as a basis for optimism about possible future functionality...
No one in this thread ever said that we will be able to cross-plant for certain. I said that he'd have to wait for customization to have a large house with herb plots (large house does not mean a modern, 50k style or a house outside of the bogs). Someone else said that maybe house customization would allow such things.
Reading the hints about customization, there will be a lot of options with yards and gardens as we will be building from the ground up. I imagine that with that, there will be the ability to make a large house with herb plots, whether it must be confined to the bogs or not.
With house decorations, should they choose to not allow cross-planting or two types of plots, there may be things like pots that you can purchase to grow the opposite of what your plots allow, though I'd expect it wouldn't allow much (maybe two or three max) and wouldn't be efficient.
Anything could happen. But one thing seems to be the main theme: there will be tons of customization of both yards and houses. I suspect it will blow our minds away when it goes in.