I recently purchased a mint condition M1917 rifle. I bought the rifle knowing the barrel was sewer piped. After a few days of trying to restore the barrel I'm beginning to think it's toast. The rifle is in really good condition on the exterior and I would like to make it an accurate shooter.

Knowing about the issues with cracked receivers on these guns who is my best bet on on getting the rifle rebarreled?

Check your same thread in the C&R section.

Try the CMP.  I can't vouch for their work, but the work will have recognizable provenance.  

I would not trust anyone other than a national recognized smith with 1903/M1917 rebarreling.  

http://thecmp.org/cmp_sales/custom-gunsmithing/