This was the response I received regarding long delays in listings appearing:
"Dear Kathleen,
Thank you for writing eBay in regard to listing items on eBay.
"Please accept my apologies for the delay in responding to your email. I
understand your concern over the delay in your listings appearing in the
category and search results.
Please understand that your listing period starts from the time that you
submit your listing on eBay. However, your item may not come up in your
searches, because our system may still indexing it for inclusion in the
Search database.
We run several indexing cycles for Search on a daily basis. However, it
can take several hours to fully index the information that we receive,
because our Search system tracks a lot of information for every listing
on eBay. The listing information includes titles, descriptions, the
auction start and end times, the seller, the bidders, and the bids.
If you revise your listing shortly after submitting it, it may take even
more time to index the information.
It is my pleasure to assist you. Thank you for choosing eBay. "