Most PIC smaller can be programmed using LVP at 5V and 3.3V but you lose the use of the PGM pin for other purposes. The PIC24+ series do not lose the the pin but regardless of that, the Brenner9L design is borderline on being able to provide enough drive current for ICSP. Also note that if you fit the 3.3V regulator, you may not be able to program 5V devices, especially with ICSP. For very little extra cost, why not build a clone Pickit 2 or Pickit 3 which is fully compatible with virtually all PICs and many memory devices too.
To me, it seems you go 90% of the way to a good proven design when the extra 10% makes it so much more versatile.
Brian.