I don't know how I feel about this development. I knew that eventually there would be non MST3K-related guest riffers, but I didn't think it would be some sort of web pseudo celebrity doing it.
I'm not too familiar with this guy, other than that he did that Mike Nelson interview for his website and he had that "fight" with Uwe Boll.
The one thing I would really hate is if they were to have a web "celebrity" as a guest riffer and it turned out to be one of these web schmucks that think they are far more important than they actually are due to whatever limited success their websites have. I don't really know about Lowtax, so I don't know if he falls into that category. I would hope not.
All that said, I think it would be reasonable to presume that the movie he would riff on would be Bloodrayne. Nothing else would make sense (besides maybe another Uwe Boll film).
Another thing is that I would not be interested in is a Rifftrax without an MST3K alumnus involved. A Lowtax solo rifftrax would equal a no-sale from me.