I have my doubts, to be honest.
Firstly, Avaya's just bought SIP application server vendor Ubiquity so this could just be a case of Chinese whispers gone wrong. (Or else they should also take out these guys for the full set of Ubiqui-things). Secondly, femtos - especially the ones that Ubiquisys is pitching - are consumer-grade, although I guess conceivably they could fit into very small offices or homeworkers. Picocells are more-appropriate for enterprise. Thirdly, they're 3G-only, so of limited use for buildings/employees with poor coverage & 2G phones. And lastly, they operate in licensed spectrum, and Avaya's sales force doesn't generally sell to mobile operators - plus, its current channel won't be able to do cellular RF site surveys, etc.
I could possibly believe Cisco might be a buyer (bolting femtos onto its Linksys division's products), or one of the large "normal" cellular infrastructure suppliers like Nokia (NYSE:NOK)-Siemens (SI) or Alcatel-Lucent (ALU). But Avaya? Seems both unlikely - and, if it happens - a big mistake in my view.
I've got a meeting with Ubiquisys at 3GSM anyway, so I'll see what I can dig up if nothing's announced.