I'd recommend you hold out for a correct period holster, rather than a reproduction. That would be something much more appropriate to the pistol.
When you get it, don't store your gun inside it. Some end up getting corroded.
The Swiss Lugers are .30 Luger in caliber, and also have that longer barrel. One of those holsters could well fit the pistol properly. The Swiss were the first military force to contract to supply their officers with Lugers in 1900. A quick look shows that Bob Simpson (
http://simpsonltd.com) has a number for sale.
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Igitur si vis pacem, para bellum -
- Therefore if you want peace, prepare for war.