RFID Guide, RFID and Environmental Issues, Wal-Mart and RFID: A Case Study

Parts of that seem awfully simplistic and light on detail.

Can anyone, for example, provide a list of frequencies and mfgr chipsets that are commonly being used by any specific vendor or group of vendors?

Make magazine, current issue

on the shelves now has a project on page 160 with a supplier for the parts that will let you build a sub-$100 RFID scanner that uses 125khz and one particular mfgr's chipset. That will be incompatible with every other frequency and mfgr's chipset and it isn't clear what RFID chips are even commonly available that this will scan.

A few other protoboards can be found via google that are sub $100 and support one frequency and mfgr's chips.

But I haven't been able to find any information on "Company X uses frequency Y and mfgr's Z chipset" in my searches.

NONE of this is for any malicious agenda on my part. Someone said he knew he was carrying several RFID embedded cards and wondered if it was possible for him to be able to read these. So I started looking to see if it was feasible to create a general purpose low cost consumer reader. Thus far this isn't looking promising.