Budget built in fridge/freezers are around £300. Non-budget ones can be £1,500+ Apart from the tasteful plating of key components with unobtainium how are these products 5 times better than the budget ones? More to the point, can the components cost 5 times as much?
O.K. - I think the break between budget and upmarket is probably the provision of a second cooling circuit and independant adjustable thermostats for fridge and freezer. However if you can build the whole thing for £300 retail then you should be able to add this for another £200 max. Where is the other £1,000 spent?
Cheers
Dave R