I have thought about having a poor condition full-length Krag barrel, lined for .22 'Hornet'. (Although, a carbine would be ultra cool)!

I envision a Liner only going about 20 inches down the bore and being machined at the breech-end, to fit within the Krag Bolt-Flange.
The extractor tip would have to be lengthened like on the Posted Sporter.

I like the cartridge, but, I'm not sure of the pressures involved.
I'd leave the receiver as "Issued". A single-shot Krag doesn't bother me.

Thanks for posting this novel Krag!