...does it really matter whether they're upstairs or down?
I've been pondering this for a while as the house we're buying has two beds upstairs and two downstairs. None are beside each other, so we'll all be a bit spread out no matter who goes where.
The upstairs ones are a bit bigger and all but the downstairs back bedroom have a built in wardrobe.
I'm going to and fro on whether we should go upstairs, and the DDs downstairs (ie we'd all be on the same floor daytime and evenings) or if it's better to have them upstairs with the bigger rooms (ie plenty of room to play) and we go into one of the smaller downstairs rooms.
As I say, we'll all be spread out, which we're already sort of used to - in our current house our bedroom is at the other end of the house from the DDs who currently share (they're 4 and 8) so we use a monitor for reassurance more than anything, as we can still just about hear them without it.
I think being on a different floor from them might take a bit of getting used to though - or will it? Do you just quickly adjust to whatever sleeping arrangements you make anyway? 