Love your second one, would make for a brilliant week

The first would be great but I wouldn't be able to watch it!

I saw a snakes and ladders task on a big brother from another country (can't remember which) but it was all huge and cool and stuff, it looked quite good

Also maybe a two houses again? But this time they are of equal importance (neither is 'next door' or 'halfway'?) and they don't know of each other (this idea seems familiar actually, someone else on the forum may have suggested something similar) but for each of the tasks, they play against each other thinking they are playing against Big Brother. Only one house can win a luxury budget, the other will live in poverty. The houses will then have to choose half of their housemates to be Endangered (not knowing what this means). They will compete in a final task against each other (now knowing of each other's existence) and the losing house will have their respective Endangered housemates ejected from the house. The houses will then merge somehow. This will all happen within, say, 3 weeks.
That wasn't bad for improvising as I'm typing!