I've been thinking about this too, although I have sorted out my issues with Gripper Burn simply by recoiling all my vn's to the 2 - 2.4Ω range, originally I thought maybe the juice had something to do with it - I use 30/70 pg/vg this has not been a problem since.
Now I can vape anywhere up to 3.8V, I like 3.2V best, I don't believe a non pwm mod will alter this, although I don't know for sure because I don't own a non pwm mod other than Twists and I don't think they count.
Because it's well known the Gripper is a little cranky and fragile, I've been looking into possible Internal swaps - I found this:
PTR08100W-voltage control (over-current protection built in) -chip. (pdf)
I know it has been used successfully in mod building in the UK, I don't know how easy it would be to swap out the existing Gripper chip and replacing it with this or if it's even compatible with the Grippers internals.
To my knowledge (limited) this is Not a pwm chip, but I too would like to move away from pwm with out the expense of moving to a higher end mod.
I'm hoping Rader and other ECF Modders could offer assistance /opinions /thoughts or experience with this chip or similar and difficulty involved in making such a swap should it be possible to do so.
Forgive my inexperience I could be writing a load of BS, perhaps I'm being over ambitious, but I am really keen to learn.