Weeeell
I put the guitars into the full mix, and got the best mix possible with the untreated POD sound. The result was quite muddy, with the bass not really being audible in its own right, and the kick drums also struggling to be heard (bear in mind the guitars and bass were tuned down to C). So, using the Focusrite Red 2 plugin on Pro Tools, I used the high pass filter to gradually roll off the low end of the guitar tracks, until the bass started to come through (my advice to anyone who wants to try this is roll off way too much then back the HPF up until you've got the right balance). Then, using the same plugin, on the fully parametric mid bands, I set the Q value as narrow as possible, rammed the boost up to maximum (+15dB in this case), then scanned using the frequency control to find the WORST possible sound (this is absolutely key). In doing this, I had essentially found and boosted the shitty frequencies...so then I reversed the boost to a maximum cut (-15dB) and the shittiness was removed.
This can be repeated for as many frequencies as you need, but I usually find that one or two cuts is enough. Obviously, you'll need to boost the level of the guitars after all this cutting, but once you do you'll find that you have a fairly devastating (in my opinion) guitar sound that allows the bass to be heard and sits nicely in the mix.
If you haven't got the gear or the knowhow to get good results with mics and amps, this is certinly a viable alternative.