I am constantly looking at this project ,myself. The .333 is a poofteenth longer (3.5") than a standard .30-06 so the action would need opening up a smidgen and possibly new bottom metal. A surplus FN Mauser 98 carbine from Columbia or R.Famage Mauser 98 both in .30-06 might do it ??? but would have to be measured.

http://en.wikipedia.org/wiki/.333_Jeffery

I reckon a bare .375 length action would be an easier way to go depending on bolt face. Stocks are available off the shelf.

Woodleigh make projectiles.

As for a barrel. The most economical way to to get the bore dimensions right would be semi-custom. Maybe TSE or AFRO (who have a good working relationship with each other) or another gunsmith can make/buy a button and make a barrel from a bored unit. TSE use button rifling acording to their web sight and I can't imagine the cost would be much different apart from setting up.

Dies would be available from CH or the custom shops of the major suppliers.

If you go .338 then you may as well go .338-06 which FATBOY404 assures me is a very good combo in itself.