Depends on what kind of Maximum Potential Intensity(MPI) formula you'd like to use. I know around here people like to use Kerry Emanuel's that is
here, which seems to work pretty well in the real-life applications we put it through.
I did find a good paper on the analysis of MPI formulas for TC's - it's not a bad read (read it
here). Of most interest to you would be the last 3-4 paragraphs in section 3 and most of section 4. Section 5 is the simplified conclusion and brings some good points out of the equations if you just want a quick glimpse at what's being said. Just search for "hypercane" and go from there - it'll put you in a good spot to start.
Bascially, though, it mentions that SST's beyond 28°C, and especially 30°C, will not increase the potential intensity of a storm and that there is most likely a limit to the intensity that is approached beyond that point. It also mentions that one of Kerry Emmanuel's older (1991) formulas, when altered to give a SST of 40°C in the South Pacific, provided an eyewall pressure of 815hPa and a central eye pressure of 622hPa . . . and that the equation broke when SST's were changed to 42°C.
In practicality though, it doesn't seem like such a setup would have a huge impact, other than providing no reason for the water temperatures to limit what the other nearby environmental variable would allow. And of course, we must also remember that 38°C water temps aren't likely to happen in today's world . . . so it only makes sense that we don't see any reason for such ridiculously high temperatures to effect our thoughts on maximum TC intensity.