You can make cases using 38 Short Colt brass (only slightly easier to find). Use PTLs as the primer (often requires dumping the powder). For the 38 you'll probably have to offset which is challenging, or modify the firing pin (only if needed depending on your gun)
Never tried for 38 but with 32 Colt you can literally swage down the thicker 32 S&W (much easier to find) and thin the rim, sometimes turn the base a bit
Another option is to rebody a case since these are low pressure rounds, if you can get to a lathe.
Castboolits has a thread on the 38 in the Rimfire subforum and an EXCELLENT one on the 32RF in the same subforum. The principles are the same.
I shoot 32 RF and tried all of the above it does work, just a hobby in and of itself.