I think it all depends on what your hoping to breed and your long term goal?
If your just wanting a larger more commercial lamb then yes, I'd think a Lleyn/suffolk would work. I've even heard of people crossing texel with Shetland with no problems.
If your wanting more commercial replacements for breeding you could put a Blue Faced Leicester on the ewes and breed Mules, which people rate as a commercial type ewe. Then cross with a Lleyn/texel which should give you a meaty fast growing lamb.