Big Button Remote

Does anyone know of a big button remote that actually works with TiVo? I recently installed an older version TiVo (TiVo HD) on my 96-year-old mother's TV (had to be an older version because she doesn't have the internet) and now I can't find a big button remote that works. We've exhausted the possibility of using TekPartner, which is the one she has used for years, and I've checked out several others that don't work. TiVo Technical Support told me there are definitely some out there, but he couldn't tell me which ones. He suggested I try posting the question on the TiVo community site, so here I am.