I wrote a small program that edits a/0/5/6 (trpoke) from HGSS, increasing the level curve to smoothly rise from 5 to 100 (Elite 4 are roughly the same level as they are in RBY, post-E4 trainers scale from their through 100 (by distance from Vermillion City)).
The beta release can be downloaded from my Github at:
https://github.com/ABZB/Gen-IV-Level-Recurver/releases/tag/0.9