The case dimensions for the 26 and 28 Nosler are identical so they could be necked up/down.
One of the site sponsors (name escapes me now) and X-Reload has 26 Nosler (Nosler cases).
However, at $96 for 25 cases I'm not in a big rush to buy one of these thing - even for the cool factor.
I would suspect that since now Browning is building rifles in both calibers that eventually someone else will start making brass (like the 6.5 Creed - originally only Hornady brass, now Nosler with others probably following soon).
At least after seeing the prices for the Nosler caliber brass I won't complain so much when I'm buying my Wby brass which seems like a bargain in comparison.