Assuming cash is not the main object (lions ain't cheap), I would start with Gray's Sporting Journal. They are, for my money, the best hunting/fishing mag out there. Very few how to's, no product placements, no "how to bag a monster buck at Wal-Mart", just well written stories about trips and recipes and some techniques. Its a bit spendy, but a hefty, beautifully bound magazine you will never throw away. Anyway, every year they publish a "Guides Issue". This is a catalog with a few articles. Thing is, in years passed (I don't know their policy now), all advertizers had their references checked before they were accepted. Also Cabela's has a guides catalog, which I know lttle about, but it too might be worth a look and they will send you the catalog for free. Also, for what you'll drop on a lion hunt, think about African Plains game. It is (relatively) cheap now. Airfare is low, the market is hurting and bargains are to be had.
FQ13 who demands a trip report. Check out Gray's regardless, you will be amazed at how good a magazine it is, and has benn for decades.
http://grayssportingjournal.com/PS a sample of some old articles from Grays, you don't find stuff like this elsewhere, I'd try The Season
http://grayssportingjournal.com/index.php?option=com_content&task=blogcategory&id=32&Itemid=78