since HPI hasn't released any details yet, I really doubt that Castle will be able to.
But, since HPI and castle already work together often, and castle has an awesome 5th scale electric set up, I would say it's pretty likely. Dunno what HPI has up their sleeves yet.
What is the setup going to be in the new HPI 1/5 4x4? By all accounts it's lighter weight than the Baja, probably savage-based, so the 2028 motor would be too big and the 1515 too small. Right now Castle doesn't have anything in between the 1515 and 2028 - so is one of the discontinued motors (1520 or 1717) going back into production, or is a new motor going into this truck?
Edit: I'll speculate that it's not the 1717 1y, because I'm guessing the Mamba XL will be the controller (for a truck that will be approximately 20lbs) and the 1717 1y is not rated to 8s (I know people run it on 8s, but that's above it's rated rpms). I think the 1520 might work, but still on the small side.
So I'll venture a guess that we'll see a new 17-series motor with lower kv than the 1717 1y, rated for 8s and paired with the Mamba XL.
Shouldn't castle fix the bugs in the Mamba XL before throwing it to the mass market with a HPI badge? Anyone remember the first Savage Flux's on 6s Lipo?