Is this a strictly IDPA holster or do you plan on carrying as well? I ask because thumb break holsters aren't very popular unless you need that retention (cop, concealed carry, ect). I carry my 229 in a thumb break daily, but I use a kydex for IDPA.
For a brown, belt holster, with an open top, I found this without too much looking.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=519377
i'd be using it 24/7 when im of legal age to OC and perhaps if i get a CCW one day.
i like the one i posted because of the tan leather and i definatley want somthing padded or lined on the inside so my gun isn't plagued with holster wear