AmmokKDE: Not that i know of, no.
A way that makes buying things back not hurt as much is to have the addon "wealthy vendors and fair sale".
First of all it makes vandors have more money, after all, they are the "rich" class. And second of all, you sell your stuff at a much fairer rate, so buying back doesn´t hurt as much.
If you want to, you can only download fair sale, without rich vendors, as you wish.
With rich vendors: nexusmods.com/witcher3/mods/6/?
Only fair sale: nexusmods.com/witcher3/mods/4/?
Hope that helps a bit.
That sounds like a good work-around. I will get those mods. The merchant interface seems a bit un-friendly, hopefully CDPK will come up with a fix for it. In the meantime, I'll be using the mods.