Dragon Magazine 351, page 92-93
Feat: Technomagical Implant (CON 13, Character Level 3)
Allows you to implants technomagical devices, which are described on the next page (93) and take up a magical item body slot. Among these items is the Tremorsense Disk, which takes up your Boots slot and gives you Tremorsense out to 20 feet. Price? 4000 GP.
Availability of implants is heavily dependent on your DM, however, because RAW they can only be found as treasure. I'd talk to him about making an adventure out of tracking one down, though.