Cool. Though teleporters might be a bit useless when grafted (except on Doc probably, since he'll be able to get support and he usually wants to play safe).

So, would the dispenser/teleporter be able to be upgraded before it's grafted? That isn't very clear.

Teleporter entrances wouldn't have much of a use while grafted, but teleporter exits would, such as having a Flanker or another highly mobile class get behind enemy lines on Payload and act as a teleporter for you, you destroy your teleporter, and set up a non-grafted one (Or the Flanker just kill binds I guess), suddenly you have a teleport behind enemy lines for your team to take

And yes, you can upgrade dispensers and teleporters before grafting them onto teammates, it's just that once they're on, they're stuck how they were when grafted until the building is detonated or the host dies (If the host dies, the building has to go through the redeploy animation like usual)

Would grafted buildings have their own separete HP or would they just auto-destroy when the person dies?

I think that the best combo would either be a sentry/tele exit on Flanker/Doctor. Flanker's good because he has the most maneuverability, and Doctor's good because he's the most likely to live for a long time. Sentry's good because it's free damage, exit's good because you usually want to be either at the choke or at the flank.

This is a genuinely good concept Enderbro. I could see it maybe being a little gimmicky or overpowered, but I do think that this would be an awesome thing to try.

Also, your sentry would probably be destroyed if you switched to this while you already had a leveled sentry built, but that sounds like the exact type of bug the devs would forget to fix.

For some reason I can't ping Goat Fanatic but

Buildings would be dropped when the host dies, but when dropped they would have to redeploy as if you were hauling them and set them down, at which point it's just a free building kill if the enemy is paying attention

The reason for this is to stop teammates from effectively griefing by just kill binding after you give them something important like your teleporter