So anyway, I had this idea, and when I ended up in an email conversation with a man whose job title said "Collection Management Coordinator", I asked if they had any provisions for someone to offer to buy them books, as opposed to suggesting titles for them to buy (which is how the conversation started--I was looking for a Web page to let me suggest purchases). And he offered to call to talk about it, and did.
The bottom line is that they are open to the idea, though the specific purchases would have to be brought before their adult collections committee for approval. He didn't expect problems there "with a well-established author". He asked if I was interested in one area of the county more than another, and I told him I'd leave that to the system to determine--I just wanted the books available. On reflection, this is a factor of my borrowing habits, where I look up books in the online catalog and request that they be sent to a branch close to me for pickup. When I'm there, I may browse the new books shelf, or the YA, or the SF (in a branch that has an SF section), but generally I just get what I requested and leave. I don't know if it's better to have these shelved where there are concentrations of other SF, or just scattered--maybe some librarian out there has an opinion. I can probably express my wishes later on, when I hand them the money. <g>
He took a quick look in their wholesaler's catalog and saw a few titles (Falling Free, CoC in trade paper??), and basically said he'd go do the research and see what was out there. I told him based on my look there were 6 or so titles that the library didn't have that are available in hardcover (FF, TWA, EoA, Shards, HH, and Miles, Mystery and Mayhem), and that I was willing to purchase 2 copies each of whatever he found if the financial commitment stayed in about that range. He seemed relieved at the 2 copies idea, and said they try to avoid having lots of titles with only a single copy in the system.