Hi Sascha,

Besides the Dallas parts, we've looked at the Winbond W77C32 and the Atmel TS80C51U2/TS83C51U2/TS87C51U2. The Winbond part is romless, 1K internal xdata ram. They probably also have a rom part. The Atmel parts are 16K rom, OTP and eprom, but no extra ram. The Winbond part is about half the price of the comparable Dallas part, and they probably have a rom version available.

Good luck,

Dennis