I looked around at several recipes but ended up kind of improvising based on the theme. Here's what I did (remember this is to make a HUGE amount, enough for 12 or more sandwiches:
-Sliced 2 onions in half-rings; dumped in crockpot.
-sliced 1 red, 1 1/2 yellow, and 2 green bell peppers into strips; dumped in crockpot.
-Using kitchen shears, cut almost 5 lbs. of beef loin flap meat (the stuff you use for fajitas; if you watch Good Eats and saw "Tender is the Loin", this is familiar territory) WITH the grain into pieces that were as wide as I wanted my strips long. Trimmed off excess fat and any silverskin that I found left on (because as Alton says, "That's definitely not good eats." Turned sideways and cut across the grain into thin strips. Dumped in crockpot.
-Seasoned with salt and fresh-ground pepper.
-Tossed (but left a lot of the onions on the bottom to carmelize.)
This will cook 6 hours on Low, then go to Warm until time to eat dinner, and be stirred just before serving.
It will be served with sliced French rolls and an assortment of cheeses (the traditional American slices, but also sliced mild Cheddar and sliced Provolone.) Each person will open a roll, put their desired cheese on, then top with meat/pepper/onion mixture, close it up and let the cheese melt while he makes his salad.
I kind of really hope there's some left over. ;)