Update on my cuben fiber tape search. Contacted Mike St Pierre over at http://www.hyperlitemountaingear.com/ regarding tape for a cuben tarp. Turns out he had a homegrown tape with cuben fiber weaved into it.
Grabbed me about 20 feet at $2.50 per foot to reinforce the ridgeline seam and the tie out seams and a some extra for any future repairs. Total weight added was 0.70 ounces therefore my total tarp set up went from 6.4 to 7.1 ounces. I'm not too upset with the added weight since I snagged me a summer quilt hopefully to arrive any day now which saved me 5 ounces in the summer.
Tape looks really well put together, matches the white cuben fiber just fine, strong, and sticks to the cuben nicely. Here are some pictures: