i have wanted to try something like this for a while. i thought it would be too complicated although sbc's are small and i have seen scematics for them and it dosent look complicated.
P.S. Back when Woz built the Apple Computer, They didnt need advanced processors and graphic cards. 2MHz was really fast. Now You need alot of power to run modern OS's. But if you can built a modern, low processor and graphics consumption OS, it might be Easy.