Commonly just BL is the replacement for Shounenai. Americans seem to have difficulty telling the difference, so here it is.
SA: The men are always effeminate both in appearence & personality, gay men didn't like it much, & unhappy endings were common. Contrary to perhaps even my own previous postings, this art is not COMPLETELY dead, some shounenai slips through the press. If it's new & fots this description, it's still shounenai.
BL: These days the men are more masculine both in looks & tude, gay men like it too, it's usually less dramatic, more sexual, & tends to end happily.
Shounenai: Ibu no Musukotachi, Kaze to Ki no Uta, & anything else from the 70s & early 80s.
Boyslove: Ai no Kusabi, BNSH, Gravitation, Fake, Ja-Dou, Psycho Blast.
Border line: Anything that lived through both periods. For example, Patalirro, Zetsuai, & Eroica are STILL being written & have made distinct changes to fit the times.