Second choice...
Well, due to the scarcity of *great* short actions for the "L" (as in lightweight) portion of the LURCR concept to be fulfilled, I would have to say the second choice would be a blued version of the same Winchester action, perhaps finished in hardchrome and/or a spray on, bake on finish for corrosion resistance.
The Dakota 76 short and long actions are absolutely marvelous, but their $1200.00+ wholesale price tag is a bit much for some. I am currently building a .358 Norma Mag on one of the long actions with a magnum bolt face.
Failing the pony up $$ for a Dakota shorty, I would make the leap to 30-06, as there are still stainless and blue versions of that in the model 70 classic available rather plentifully.
It also opens the door to creating a rifle based on other classic actions like the P14/17, the Springfield (my all time favorite), the Mauser, etc.
The LURCR is designed to be a lightweight short action concept, but there is no great whopping reason that you can't make a little more weight go a long way. The 30-06 is a great choice, but the .280, .270, and 6.5mm-06 could be great choices as well, depending on what the rifle is intended for. They all offer greater range than the .308 due to their flatter trajectories. All offer superb accuracy as well, when built correctly.
I would gladly build rifles on any of the above mentioned actions and calibers, utilizing the rest of the LURCR principles to the largest degree possible.
Maybe call it a SLLURCRR (Slightly Less Lightweight Utility Rifle Concept Re Redux)