I've been in search of the same FOR EVER with no luck. So I'll be watching this thread. I bring tequila back from the US every year because I can't find it anywhere here.
"Sierra" is the brand with the Sombrero and I agree, it ain't tequila. However, the black sombrero which isn't very often carried, but can be found at Kartstadt, is pricey and not half bad. We had it at a birthday party and did shots and it went down surprisingly well! In cocktails I imagine it's a charm.
This delivery site carries Sauza, but I don't much care for it.
http://www.doit24.de/?gclid=CK-Lu_Wd_pACFSgfaAodTCt22gI bought some Cuervo Gold at the Airport. I've never found Padron.