Not extremely rare but more scarce than a full octagon or full round barrel.
Depending on condition and any more special order features(pistol grip, sights, checkering, grade of walnut, barrel length, 26 inch is standard) value could be from $600 to $5000 and up.
A friend has a 94 which I think is worth more than $5000, it's features are as follows:
Model 1894 takedown, extra lightweight
26 inch half round rapid taper barrel
pistol grip
checkered stock
3x walnut
shotgun butt
original sights
Original tang peep
.30 WCF
1899 Date of Manf.
Set triggers
It letters correct as having left the factory in this configuration.
It's the nicest 94 I have ever seen as well as having about 90% finish remaining, even on the action which is unusual.
Needless to say these are few and far between.