Yes, you can use the ispPAC-POWR6AT6 with the I2C interface to read voltages back through the VMONs. The ispPAC-POWR6AT6 has a standard slave mode I2C interface and can be hooked to an FPGA, microprocessor etc. to read the Analog to Digital Converter, (ADC). This is an inexpensive way to do voltage monitoring and take advantage of the differential VMON inputs.
See the following link to the datasheet:
http://www.latticesemi.com/products/powermanager/powermanagerii/powermanageriipowr6at6.cfm?source=sidebar