Well
Forestclimber, if you want to be innovative and build a one-of-a-kind, think about this.
1. Find yourself something like a cheap used and abused Omega.
2. Remove the breech assembly from the barrel.
3. Purchase a Green Mountain 42" x 15/16" slow twist .54 caliber barrel (
http://www.gmriflebarrel.com/productdetail.aspx?id=323896).
4. Cut the GM barrel in two, 12" from the breech end. (Save that 12" section for a pistol build next year.)
5. Have the 30" section machined to accept an Omega breech plug.
6. Fit the Omega action to the GM barrel the same way it was fitted to the Omega barrel.
7. Bed that sucker in the Omega stock.
8. Take plenty of pictures along the way and report back to us.
9. Now you have yourself the world's only octagon barrel .54 caliber slow twist Omega.