Simultaneous extracellular recording from different distant sites (in rodents) I wonder whether it is technically possible today to have simultaneous extracellular recording in awake rodents (e.g., mice) from different non-proximate sites (e.g., V1 and frontal cortex). I mean to have two or more different electrode penetrations at the same time. Using multi-array / grid / tetrode  it is possible record from many locations, but they are spatially proximate. Any references are appreciated.
I wouldn't know why multi-site cortical extracellular recordings would not be feasible? What would the practical experimental or technical limitation be in your opinion? 

As long as you have a multichannel amplifier suitable for extracellular recording and you consider the choice between using a common reference, i.e., monopolar recordings (Ludwig et al., 2009), or using paired recording-reference electrodes for bipolar measurements (Boatman-Reich et al., 2010) you should be fine. 

References
- Boatman-Reich et al., Front Comput Neurosci (2010)
- Ludwig et al., J Neurophysiol (2009); 101(3): 1679–89