Gordon, for hobby use, I think this should work fine, so long as you match the pressure angle.
For the same number of teeth, DP and MOD do not by themselves indicate any difference in shape - involute is involute. However, pressure angle DOES indicate a difference in shape, and I have found that when it comes to inexpensive and widely available gear cutters (e.g., eBay imports), most MOD cutters are 20° while it seems easier to find DP in 14.5°.
So the shape of the teeth is the same for the same pressure angle and ... what about the size of the teeth? DP and MOD are reciprocal methods of describing the size. DP is typically based on a pitch diameter (PD) measured in inches, and the relationship between the number of teeth (N) and the pitch diameter (PD) is as follows:
DP = N / PD
Meanwhile, MOD is typically based on a PD measured in mm, and the relationship between N and PD is the inverse:
M = PD / N
So, taking into account the conversion from inches to mm, the relationship between DP and MOD is as follows:
M = 25.4 / DP or DP = M * 25.4
So, 48 DP is exactly the same size as MOD .53, assuming the same pressure angle, or conversely, MOD .5 is exactly the same size as 50.8 DP. As you note, the difference in depth of cut for a M .5 vs. 48 DP is only .003" ... and in fact, different reference works calculate the clearance differently, so the depth of cut for an M .5 could be given as .044" rather than .042 (and .047" for 48 DP rather than .045"). Thus, that .003" difference is down in the plus-or-minus error range.
All this to say: for hobby use, given the compromises inherent in gear cutters, etc., I can't see any reason it wouldn't work. Just make your OD based on the calculations for 48 DP, and cut the gears .003" less deep. Done!