Not really.
DS Game Maker has nothing in common with RPG Maker VX, you would need to reprogram everything making all the work you made on RPGMVX useless.
As for devkitPro, it only lets you develop for DS with some base libraries.
You may use it to create some engine from the ground up, let's say, you own version of a completely new RPG maker of your own.
It may take a couple of years to complete for one person that has to learn to program.

PS: Why don't you try making it directly on the DS, using RPG Maker DS+. I haven't used it, so I don't know how limited it is, but it may or may not be OK for you.