Earlier quoted context omitted.
I've mostly solved the cable problem using monoprice.com. They are about 25% the price of a radioshack or other intown store. So when I place an order I buy 3 of everything I might need and keep them in a box, including a couple really long examples of each cable. It's cheaper for me to keep inventory than to buy local. I use the long ones temporarily if I run out of "right length" and swap when the next order comes…
Upvoted for how relevant this solution is to my own cable needs. I definitely don't miss the cashier trying to convince an electronics entrepreneur with engineering in the blood that 6' $80 HDMI cables have a noticeable quality difference. Still, I haven't found a good source for prototype project boxes in Radio Shack's price range. Can anyone recommend a low-cost rapid-prototyping plastic case manufacturer?
Polycase is carried by Allied (www.alliedelec.com) and has some inexpensive, decent quality plastic boxes for around $3-4. I thought of those immediately after reading your post.