I write drum tracks in Guitar Pro using standard General Midi note numbers (#35/#36 kick, #38/#40 snare, etc.), then use MIDI-Yoke (a virtual MIDI port) to redirect the notes to VSTHost (a tiny standalone VST host), where I can listen to the song before moving it to my DAW.
My problem is that the drum VST that I use has note mappings that differ from the standard GM mapping (say, my kickdrum is #40 and my snare is #55). I'm looking for a no-frills, intuitive MIDI VST that allows me to re-map the notes one by one, and save those maps.