AzMedic,
I received my P1887 rifle sling from Turner & Co. this past May.  It is well worth waiting for, and the price was $99.25  including shipping.  I have three(3) of there slings, and they are holding up very well.
Now rigging this pattern of sling is a real PAIN!  Fortunately there is a instructional You tube video that will walk you through it.
Are you planning to attend the CMP matches at Ben Avery this coming October? I am entered in the Vintage Rifle matches with my M1898 rifle, and my SMLE No.1.

Irish Mck
1st Arizmilitia