The mbira is well made, feels really sturdy. I visited Sebastian when I went to Amsterdam two weeks ago - he lives in Neunkirchen-Seelscheid, Germany. He lived in Ghana for ten years, was building drums there, has been several times in Zimbabwe and learned mbira from great zimbabwean player. He showed me number of mbiras, different types, different chunings etc. As I didn't have enough money with me to buy the mbira immediately, we agreed I'll send him money via PayPal and he'll send me the mbira. He sent it on Friday, I got it on Tuesday. He's nice guy to deal with, he showed me two sets of bata he build too (he didn't have skins on them, so I can't say how they sounded, but they were made from one piece of wood and looked very nice), and he builds other drums too..
You can check the sound of one of his mbiras here:
http://www.youtube.com/watch?v=-j5ymyRg_Gk , mine sounds very similar.