What do you think of the TRX RIP Trainer? Here’s a link to it: http://www.trxtraining.com/products/trx-rip-trainer-basic-kit
Personally I made my own rip trainer by using a piece of pvc pipe purchased at home depot, got two end caps, drilled a hole in each, then put an eyelet hook thru tightened a nut with some thread sealant, and i loop a resistance band purchased at elitefts.com to one end of something (this is the anchor) and the other end gets hooked to the eyelet hook with a carabiner. Works just like the try rip trainer and cost about $15 bucks to make. I love it!