Short answer: You can call redline up and order it direct.
If i understand correctly, you are probably really looking for the 5w20 stuff. I have an 03 civic that specs it and summitracing didn't carry it, neither did any local shops. I finally ended up calling redline to see if they even made 5w-20 for street use, and they said "sure, how many quarts do you want?"
The coolest thing was 3 days later when a fedex guy walked up to my door with a case of motor oil on his shoulder. funniest thing I've seen in a while.
I'm using the 5w20 in my Civic, 3K filter change, 6k full oil change. I feel like the oil is doing just fine, holds up nicely, and I haven't noticed any kludge in the engine. at 3K the oil was a bit dark when I changed out the filter, but it has stayed the same shade with the new filter. I'm about to change again in 500 miles so if you wan't I'll keep you posted.
FYI, if you look around the board, most poeple use mobil 1 or amspil for longer changes.. I use RL because while I don't race, I drive in California and on highways where the "speed limit" is more like 80 and both tempers and temperatures get kinda hot, and I end up driving a bit hard at times. If you are easy ont he car, Mobil 1 syn might be a good choice, too.