Look around, many suppliers have barrels in stock if you have leeway on the profile. Brownell has Shillen and Douglas in stock. I bought a #3 contour .308 bore barrel from stock.
Now if you want a spiral fluted, gain twist, X contour, in 9.3 caliber your going to wait. Choices always choices.
My other suggestion is to order a replacement barrel when you build your custom rifle
, especially in high volume, overbore cartridges. So if you take a year to put 1800 rounds through your 6.5-06 or 6.5-284, you'll have your replacement when needed.