The issue you are seeing is a bug in the i2cdev.m. We will fix the issue and update the support package. In the meantime, here is a work-around. Edit i2cdev.m which is located at:
assuming you installed the support package to the default folder 'C:\MATLAB\SupportPackages\R2014a'. Change line 59 from:
if ~ismember(obj.Address, devAddresses)
if ~ismember(lower(obj.Address), devAddresses)
I verified that I can create an i2cdev object to a device at '0x1d' given the output you provided for the scanI2CBus method.