Cheap good quality Linear Power Supply

[bencat]

Many of the modern digital boxes that some of us use such as Dac,s , Media Streamers etc have either very cheap built in the plug power supplies or switch mode supplies. It is often commented and suggested that a good basic linear power supply replacement would give a good lift to the sound quality in each case.
However most of the ready made units offered for sale are priced above the cost of the original unit complete never mind the supply and this makes things difficult if you are on a budget.
Would it be possible to offer both a kit and fully constructed version which would be reasonable in cost but a real improvement on the original supplies ?