I'm lucky, my lcs has enough custom for new issues to allow the owner to also focus on back issues. He also has good contacts in the States and often buys in silver and bronze collections from there.
He has proper wall books which currently include; ASM 1, DD1, GSX 1 and Uncanny Xmen 94 to name a few.
So few comic shops sell back issues now, but he loves it and makes good money doing it.
I was in there last week when they were filling their regular pull lists and it was incredible, piles and piles of new books being put together for customers.
Mind you we have had a few shops fail here over the years, but he runs it like a business and it seems to be working.