Does that include having an FFL store your firearm for the duration of the period between special e-form 1 and issuance of the tax stamp? If so, then that isn't a viable alternative to resolving being in possession of the newly designated SBR without the tax stamp.
If you already own SBRs, then you missed a once in a lifetime opportunity to get another one free of charge. Pity.
I already have the NFA trust and all parties have current photo/responsible person information filed. I don't really want another SBR, but another suppressor that handles 30 caliber is on my "want" list for the 300BLK SBR. I built it with a 10.5" barrel as optimum for 300BLK and just right with a suppressor attached. In recent weeks there has been discussion of feral hog problems in Montana and Wyoming. The 300BLK is ideal for hogs.
After the rule posted, I don't think any FFL will accept an unregistered SBR into his inventory. FFLs must also register all braced pistols in their inventory just like individuals do.
So no, I don't think your hack would work.