I notice you also posted a while ago about fitting mk3 hubs. You realise you could kill 2 birds with one stone and get a whole front setup from a mk3?
The only reason I'm chucking this idea into the pan is because the cost of 280mm carriers and calipers seems extortionate (I think up to £100 even without the discs) due to their popularity vs supply. I noticed this when hunting for a project car.
I've no idea on the cost of the mk3 hubs, brakes, wishbones and driveshafts, but I wouldn't be surprised if you could get a setup at a similar price from a breaking car and they're bigger than 280mm. It might be a wider track too.
Since I'm ignorant to the pros and cons of all this (only since buying my mk2 have I realised you can do this), feel free to counter my idea!