This isn't for hard core low-carbers by any means, but there is another low glycemic bread on the market - from Albarado St. Bakery. I found it at Whole Foods today. They actually tested the bread with Glycemic Research Institute and it says GI of 5 and glycemic load of 0.9 per serving (34g for slice). Its ingredients are mainly sprouted grains (but much tastier than Ezkiel bread.)
Diabetic Lifestyles Low Glycemic for Diabetics: Alvarado Street Bakery
I ate one slice with some chicken (and had some salad dressing that had 3g of sugar!), so it's hard to say, but my BG rise seemed relatively small (rose about 15 points in 1 hour - now 7 points down from that in 1.5 hours).
BTW, I consume pearled barley also - it gives a very very slow rice in BG and it raises my GB only moderately.