I didn't catch any requirements in terms of rail or attachment preference. It's interesting Scotty, because I was in this exact same spot a couple of weeks ago. I got some pretty good advice also. . I went with SLR, and I could not be happier. However, had I been aware that Centurion would magically show up with some rails available. I would MAY would have waited. So here are some options that were shared with me from WEVO when I was asking the same questions:
This is the rail I bought. It is lightweight, it seem rugged enough. I've heard nothing but good things regarding their parts.
Centurion CMR handguard (A likely replacement had I not gone with SLR)
Cross Machine & Tool: CMT, Good stuff, highly recommended.
Good luck, let me know if you have questions about my SLR. I posted pics in the custom build and in the precision semi-auto thread, if you want to see it on an AR. I'm with you, I only have rail covers and a bipod.