A TorsoLite pad would be perfect for you; I just posted one for sale in Gear Swap. ; )
I'm kidding. I doubt you'd be happy with the TorsoLite, which is at the opposite end of the spectrum from a size large Thermarest.
From my my own experience, and reading the sleeping pad threads and reviews, I've concluded that sleeping pad systems boil down to personal preference and need. Balancing a combination of weight, comfort, and cost, and in some cases, bulk, durability, etc., results in lots of varied opinions.
With that in mind, you'll get more useful feedback here if you provide more details, such as a description of your priorities; weight, comfort, cost, bulk, what you've used in the past. How much cushioning do you think you need? Intended temperature range? Sleeping on snow? Environment? Some places are much rougher on self-inflaters than others . From reading the forums, I have the impression deserts seem harder on inflators than forested places. A large is wide at 25", most folks frequenting this forum probably use a 20" wide pad or less. You can save some weight by going with a short Thermarest, and using other padding (closed cell foam and/or pack, etc. under your legs).