1000hp small block or big block mopar builds were a niche market to begin with, and I'd imagine it's getting even smaller with guys jumping ship to gen3.

Looking for a 1000hp capable block for cheap? How about a whole fully assembled short block for under 4K?
http://www.modernmusclextreme.com/p-215-hellcat-62l-hemi-short-block-68262362aa.aspx

Guys are pushing their hellcats to 1000rwhp on that stock short block so I'd imagine 1000hp at the crank wouldn't be so risky (assuming you're using a turbo or blower, not spinning it to 9k N/A).

This is the way I wish I went with my car. I couldn't afford to drop 2500-3k on an unmachined R block then pay another 3-4k for a rotating assembly and machine work so now my stock LA block is my limiting factor and i'm afraid to push it over 650hp. Doing the math on it, I think I could have done the late model hemi for close to the same cost and I would have had a far superior power plant, not only in its ability to make and handle power but in drivability as well.